Interesting, I remember using this as my final project for high school calculus. If we treat the track as a function, the time it take for the ball to travel the track is ROUGHLY the integral of that function (area under the graph). the less area under the track, the faster.(actual velocity function involve square root of the graph, x-axis is distance, not time. t = ∫(dv/dd) ) this also apply if the ball start with some velocity or if the track has loop like roller coasters. Just need to adjust the boundary intervals and treat the loop as piece wise function. also, we can model the friction use the concavity (or second derivative) of the function, since both of them are proportional to the normal force the ball exert on the track.
There's nothing inherently wrong with 'rate of speed.' it's not like saying a high height; it's like saying 'measure of mass.' A little redundant, sure, but nothing wrong with it. Also, speed and velocity are interchangeable until you choose a coordinate system.
That's all well and good, but the low road ball never actually reaches the "end" of the track. The low road will always be faster, but never go as far. So depending on what point you actually assign as the finish line, the high road may be faster in the sense that it is the only one that ever actually finishes.
Kur Norock. Thats a bit of a nonsequitor, as you can also argue that both balls don't exactly make it back to the starting point. What remains is that the extra conversion of potential- into kinetic energy gives the long track a net speed advantage. (Even though it has to again convert that kinetic energy back into potential)
I noticed that as well. The slow motion replay always seems to stop just before the ball on the high track reaches the end so we never get to see if it travels a greater distance.
Joel Dodson. It doesn't travel a greater distance!! In the given tracks, both balls travel the exact same net distance. The difference is that the ball on the longer track gets more speed from a higher vertical drop. Unfortunately the experiment suffers from friction (on both tracks), which results in energy loss. Friction is proportional to speed (so the faster ball loses more energy) AND on the longer track the friction works over a longer distance (so the ball loses more energy). The energy loss (in both tracks) mean that the balls will come back to a lower point every time.
Dozo G I wasn't talking about when the balls return, I was talking about when the reach the end of the track. The ball on the longer "low road" always stops a bit short of where the ball on the flat "high road" track stops.
At what point do you experience diminishing returns on this? I imagine in the degenerate case of an infinite drop and an infinite rise, no amount of speed could be enough to cover the infinite distance of the dropping track faster than the straight track. So when do we hit an optimum drop distance / track length ratio?
the problem with dropping the ball too far is that it converts some of it potential energy into rotational kinetic energy, as it climbs back up this energy is needed to be converted back to potential again to get the ball to the top. If I make the track too steep, the ball will lose traction and can't make the climb. I find this to be the limiting factor so theoretically the ideal distance for the drop may be different that what will actually work.
If you're interested in the answer on where to expect diminishing returns on the case where the rotation of the object can be ignored, look up the brachistochrone problem, which is the name for this question in classical mechanics. (Spoiler: the most efficient path is a cycloid.)
Zekian Hmm, but let's ignore for the moment friction. Neither ball rotates as it slides down either track, and there is no air resistance. The question I'm asking is about the speed gain from the potential/kinetic drop/exchange versus the cost of making the path longer. Was that the cycloid answer from before?
Reminds me of the brachistochrone problem. Cool video, your students are lucky to have someone who has such a knack for making non intuitive results as easy to understand as possible.
Bruce Yeany That would certainly be interesting to see. I think you'd enjoy some of the videos by 3Blue1Brown, they have a knack for approaching various mathematical problems in ways (often geometric) that give additional insight into how everything is interconnected, such as how the brachistochrone can be solved using both Snell's law and as the path of a cycloid, or how the solution to the Towers of Hannoi is the same as binary counting/the path through a Serpinski triangle for the constrained version.
@@YeanyScience No different than a gear or pully... the slower ball actually travels further each time on each end, if you look closely, the balls aren't actually traveling to the very end and not to the same length at the end points... The one with the curves is like the big sprocket on the back wheel on a 10 speed and the straight line is like a smaller sprocket on the back of a 10 speed. The two balls are also spinning at a different rate so the Torque is also different. The curved path provides more torque and can't make as close to the end-point, but the straight path has more horsepower and goes further up toward the end-point. Since the energy must be conserved, the straight line ball trades going further toward the end-point with a slower time, the faster ball trades a faster time with going less toward the end-point. Interesting experiment. If you changed the diameter (and even the mass distribution) of the ball you could fine tune the speeds and how far up the last incline each ball went... you could get very close to no improvement in speed by using balls with less or more diameter in comparison to the design of the tracks... one ball is traveling further and higher (more distance up the end-point) and has more force, but doing it over more time... while the other ball is traveling less, and lower (less distance up the end-point), but doing it faster... so all that is change is time, it's a sort of time dilation.
Mr. Tangent yes technically to fully go with the scientific method and eliminate as many variables as possible, he should have. but u can see that he started giving the straight line ball a bit of a head start to prove his point. I think the experiment serves its purpose just fine.
I actually use a path like track two in War Thunder to catch up to bombers since you accelerate quickly to your top speed and then end up able to open fire from directly under them while still having enough energy to escape most of the return fire.
The aim of rolling scissors is to reduce the closing to the bandit so you can stay behind his 3/9 line (while he does the same, so you both end up doing this kind of barrel roll around each other). I guess you mean that this experiment would be more similiar to a lo-yo-yo, where you want some closing into the bandit.
The maneuver that I was describing is only valid if you are well below top speed and are at an equal or greater height to the target. It brings you to top speed quickly, and puts you in a good position to attack. You just have to make sure you wont pass low enough to get in any enemy fighters range on your way to the target.
Nice demo. Slight correction You say the track lengths are the same. Both I think what you really mean is the horizontal distance the ball travels is the same for each ball. If there are any scouts who participate in the pinewood derby this is a really good lesson for them.
Nathaniel Schmitt How or why do you think it comes down to aerodynamic? If you think about it aerodynamics has almost very little to do with it at the speeds pinewood derby cars race at. This is a great example of where math would give away the answer. The Drag equation even proves it. It turns on there are really only two factors in determining which car will win. Friction and PE. Fiction plays a big part in which car will win. There's frictional drag from the wheels rubbing against the side of track and and then there's the friction from the axles. What's being demonstrated in the video is just as important too. Too bad the teacher didn't explain the energy math. The math would explain's it perfectly. it. Not sure if you took physics, but if you had you would have learned about PE and KE. Just to refresh PE=MgH and KE= 1/2 MV^2, Ignoring friction and look at he PE. Just like in the video. Looking at the KE one would expect the car with the highest velocity to win. Here's something to think about. If you have two identical derby cars. Same weight, same aerodynamics same frictional forces how is it one car can have more PE and win every time? (This is the secret.of how to win.)
This was fun. We used the sum of potential and kinetic energy in mechanics problems all the time, yet I've never seen this concept demonstrated like this. It was very pleasing to see just how clear the results were.
but you can also see that the one with the slopes doesn't go as far up the return slope. meaning in theory it isn't actually traveling the full distance. maybe a small Tiddle to think about.
If you would make the tracks the same length, they would end up at the same height. Now the ball in front travels a greater distance, so it experiences more friction, thus it doesn't reach quite as far back up.
Why I loved science teachers like this. The things they built to show science were simple yet well measured and built. The mess of bulletin board patchwork behind him is great since this guy is obviously capable of decorating with precision instead of chewing the paper apart. Learning tool or pretty decor? Easy to tell this guy chose to engage around his subject and knowledge instead of making his room feel fancy. Nothing against the pinterest mafia but this guys prep time is well spent.
If everything else were equal the only difference would be the actual distance between the two tracks. If both spheres start with the same energy, they should both be able the same overall "distance". I believe they might actually stop at the same time. But the one with the hills may stop first since it travels faster at points, expending more energy over a shorter time. If you still have the setup I'd love to see it. Maybe fast forward a bit.
The flat surface jas a constant friction, it can use up all potential energy as kintetic energy. The one with the hills have a peak which requires alot of energy to overcome, at some point it has enregy left, but not enough to travel over the hill. It will waste energy and therefor traveldistance. That is at least my hypothesis
if you look closely, the shortest path allows the ball to actually move up the end ramp and start ramp, on its return, a little further. This is expected since there is less irreversible energy loss (sound, friction) on the shorter path. This concludes that you can actually get more work done with the shorter path ramp since it has more momentum at the ends.
SamBskate That was the first thing that struck me when I started watching the video. Those two tracks are NOT the "same length"... the one that is closest to the camera, clearly has a longer surface area for the ball to traverse than the piece of track that is closer to him.
Alex Thatcher ... The gentleman in the video said that the length of the two tracks were the same, and they are clearly not the same. But, in order to put an end to this debate, we must agree that we disagree :)
All I know is from 10's of thousands of cycling miles, I can build up quite a bit of speed on the downhill, and generally carry it to the top of the next before sitting down again. Where's riding across Kansas was pure torture. I realize the equation us mire complicated, by the feeling says it all.
Actually Emmanuel, that shit would work. You see as long as the frictional force is compensated at the top of the hills and Visfor doesn't eat shit on pavement, he should be able to travel a longer distance because he has sections of high speed and almost no work.
it ll only work till the peaks are at lower level than the starting point...the additional energy the balls are getting due to higher potential energy is converting into KE... once the peaks get higher than intitial point...the KE ll b convert onto PE with some loss in energy n the ball ll slow down...so it depends on the hills
Michael Faux hey, nothing wrong with High School level questions. This isn't a college level course. I do grant they could google it, but that does mean they should. I don't think they are "retards", maybe just a little lazy for not looking it up themselves. Still they could be watching Minecraft or react Videos. I'd say that hostility to people who are wanting to learn won't help anything.
There is a competing principle where the faster ball experiences greater drag (loss of energy) because drag is proportional to velocity squared. At these low speeds however, its a minor factor to this outcome.
I think the misperception that we get when we originally look at the scenario is that the extra drop and rise would cancel itself out. A very interesting video
lol yea but he did say in a comment he teaches to 7th and 8th grade so generally the way he would speak and the terms he would use for the younger people would tend to become habit.
The fact you still knew what he was talking about makes the choice of words irrelevant. If you knew what he meant, even slugs will understand. All words are made up.
a cool little addition is that at any point that the two balls are at the same height, excluding loss of speed from friction, they should be moving at the same speed. It would be cool to create a track that is even in the front and back at the middle to show this. also, adding curves is kind of like calculus. if you were to add infinitely many drops to the first track, it would begin to behave more and more like the 2nd track. (sorry if you already pointed this out)
I just watched your "Solar motor--Free energy motor" video with my three boys and we all loved it. I will probably try replicating and enhancing that design and see if I can get it to power a small generator. I have also learned that the term "free energy" means different things to different people. I have always naturally thought of things like solar energy and atmospheric electricity as free energy sources but under some folks definition nothings is "free". Anyway I know how much work making videos is and I really appreciate your content. My boys are already flying magnus effects cups around the house.
excellent!! if you want instructions for building, send me an email address and I will forward them to you. I have a quote on my wall that sums up my mind set, Sunlight is free until the government figures out have to tax it. My idea of "free energy" is tapping into ones available without costs.
The high road ball always wins - marginally. Watch closely and you'll see that the low road ball in each case doesn't go as far up the ramp on the far side.
He's making a point that both tracks have both ends at the same height. Or as he wrote in a comment: "I did carefully pick the height of the humps, they rise to the same height as the high track but not higher." So the "finish line" is the end of the track. I find it noteworthy that he makes it impossible to see both balls slowing down on the way back every time, either by stopping the recorded video before the slower ball gets back, or by picking up the faster ball before it slows down to 0, while letting the slower ball roll to the end. I can only conclude he's doing this intentionally, because he does it every time. If he would let the balls roll until they don't roll up anymore, the faster ball will actually stop sooner due to friction, since the curved track is longer.
Walter W. Krijthe He's stopping the balls intentionally but not to cover up the fact that faster balls will lose significantly more energy due to air resistance increasing (as another said, 4x per 2x speed), or that longer tracks will create more friction. He's simply making the point about the conversion of vertical potential energy into lateral kinetic being more time efficient. It might be energy inefficient, but that's not what he was describing. What is with this kookery? That everyone thinks all others have a secret agenda to manipulate their world view via fucking basic physics.
I still don't get it The PE generates more KE on the second track, but shouldn't this surplus of KE be consumed for lifting the ball up the hill? I mean, I expect the ball to have higher speeds at the downhill, but lower speed (than the other ball) at the uphill so they compensate can anyone explain this to me?
chromme the balls have the same PE, but the key is that during the period when the lower ball has a higher KE, it is covering more ground at its higher speed, and the ball with constant KE never makes up that difference. So at the end of the track, the balls are going the same speed, in the low portions, the lower ball is at a higher speed
chromme ok, the faster moving ball over a distance, can get enough of a lead that it doesn't matter that it slows down going up. if the tracks were extremely long and there was friction/air resistance, the faster moving ball would have an even greater lead. So it really depends on the length of both tracks. If the track was short enough, then yes the paths would have the same completion time (the track would have to go down and right back up).
if you imagine it to be an ideal system, than the second ball will start going faster when it falls and when it ascends it will just "reset" to the speed of the "normal" ball and it will not ever go slower than the first ball thus making it faster overall. this one is not an ideal system but the friction is low enough to see the effect.
You’ve designed the track for a specific outcome. The harder design and the better lesson would be having the balls finishing simultaneously in my opinion. I appreciate your time and effort to make this.
carl witt it is not traveling as far so the time it spends being slowed by friction is less. Therfor when it reaches the other side it has more energy. This is why roads are flat not a set of hills flat roads conserve energy. Hills consume more but have higher acceleration in the first slope.
Pseudo Mortality in the Electrical code, any receptacle with a metal faceplate must be positioned with the ground prong up. This prevents a short circuit in the case that the faceplate were to fall off, as the faceplate would only touch the ground prong as opposed to bridging the hot and neutral.
Wow that is amazing that the wall outlet is upside down usually showing that it is a half hot outlet! One receptacle would always be hot and the other would be operated by a light switch. Amazing! Oh and I loved your video. being a Sailplane Pilot I use this technique all the time between thermals and porpoise fly as much as I can.
Twelve Seven I knew there'd be calculus in there somewhere. I was thinking that the times would be the same if the average heights were the same. What do you think?
Alex Snitzer by the looks of the balls and I think because of some laws of physics, there is no possible way the ball could climb above the other one of both start at the same height
Alex Snitzer O MY FUCKING GOD. YOU'RE ON THE INTERNET, LOOK UP BASIC PHYSICS. facepalm facepalm. You have a potential energy at the start, that translates to a maximum kinetic energy at the midpoint, half the distance from peak to peak of an even curve. so you come back up to the starting point.
Alex Snitzer here is a simple test for you. Take a bowl, release a marble from the rim. note that it doesn't jump out of the bowl, it just goes up and rolls back. it doesn't have the energy to make it higher than the STARTING POINT. Really simple.
No, the energy in both tracks is the same at the end if you don't consider friction If our roads were dipped like the track we would be traveling extra distance, resulting in: more distance that air can drag on the car, More energy lost to friction in the drivetrain and tires Speed limits regulate max speed anyway, meaning we cannot utilize the PE to KE conversion displayed here
Markus Andreas no because the the energy used to make it faster is taken from the energy to make it travel far. So you might me going faster than a flat road but you won't get as far
So if you are flying a single engine plane and lose your engine you find the perfect glide speed so you can glide the furthest distance. Would this concept apply to aircraft as well? So instead of finding the optimal glide speed, try to make the plane climb and fall 100 feet at a time, making the plane go faster extending its glide distance potential?
You are misunderstanding something here. The ball on the "lower"/wavy track goes faster, but both balls have the same amount of initial energy. If he were to let the balls go back and forth until they both eventually stopped, you would find that the "lower"/wavy track ball stops first. But if you were to measure both tracks, you'd find that both balls traveled more or less the same distance overall; one just uses its energy at a faster rate. As for your question about the plane, the more important "distance" is distance measured across the Earth rather than the actual distance the plane travels. Thus, the optimal glide speed is going to end up with far more Earth distance than a wavy track would; though the plane would travel the same actual distance regardless, the glide distance in comparison to the Earth would be far more if the line was straight.
Crazy Nate Also, this wouldnt be a good move because the velocity would change depending on position in the "wave", faster on the bottom of the wave and slower at the top, meaning that absolute optimal glide speed couldn't be achieved all of the time unlike in straight motion.
the lesson that we can learn is, in this life if we got so many problem just believe its increase your speed for your goal. but if you just got a straight way or flat way maybe be you just in cozy place, because life is never flat.
the two tracks are not the same height, the straight one has a much lower ball release height, if you made them truly the same the result would be much different. the height of the track is determined by its lowest part NOT at the physical point of release, following your model you could have a 60 foot drop covering the same distance and as long as you line up the start point you would say they were the same height.. your experiment is flawed.
Gail Raby the end point is the same height and so is the start so the potential energy and kinetic energy in both balls is the same at the start and end
the actual height it's travelling at has nothing to do with the end result, it's about the journey to that height. and your example of "following your model you could have a 60 foot drop covering the same distance and as long as you line up the start point you would say they were the same height" makes no sense; the END point also needs to be the same height.
+ThePizzabrothers Gaming I am not about to explain where you are wrong but wrong you are.. the two tracks are NOT the same height, the flat track has half the drop of the other.. that alone explains the difference in speed...
One thing not mentioned here is how the rotational energy from the balls affect this experiment. The increased rotational speed of the lower tracks allows it to travel back up the hill without losing as much kinetic energy. Try to on a track that doesn't allow the balls to rotate and you'll get different results.
I have a question. The "low road" ball speeds up going down hill due to gravity (potential energy turning into kinetic energy), but it also slows down going back up hill (kinetic energy turning back into potential energy). Why doesn't the down hill and uphill actions cancel each other out?
If I were to think of this as a graph, where the flat track is the zero axis of Y, then every drop below the Y axis would equal an acceleration along X. Therefor the only way to cancel out the acceleration is to make the lower track rise above the Y Axis. This is a great way to understand the relationship between Potential energy and Kinetic energy.
Don't know if you have tried this, but if you made one end of the track horizontal on each, the balls could then act as projectiles and should travel the same distance horizontally before hitting the floor. That would demonstrate that they had the same KE at the end of the track since they started with the same PE at the beginning.
you would eventually get to a point where its kinetic energy stops increasing and the straight track would win, albeit you did prove it would take quite a distance. fascinating video, if i could take a physics class again i would
Love the experiment, always cool to see these ideas in real life. Just one thing. You cannot have a "rate of speed" for two reasons. First off, "rate" has to be followed by a "change" word (eg. rate of increase/decrease/change)(unless you're talking about something being priced at a "good rate"). The second is that speed is a word for a specific type of rate - that is distance over time. Saying "rate of speed" is like saying "the rate of the rate."
you should build one in which the lower track is a parabola shaped such that the balls do arrive simultaneously. It would have to sit on the edge of a table to accommodate the low track but other than that there really shouldn't be any feats that go beyond a few simple calculations.
cool to see! it would have been nice if you also explained that the balls have equal speed when they are at the same height though, and you could have also shown us which one experiences the most loss in energy over time (im thinking there are multiple reasons for the more bendy and longer tracks have more energy loss).
I like your videos...want to point out that the low road is the hare and the high road is the tortoise ...same energy farther distance...eventually the hare takes a nap while the tortoise keeps on going
Excellent demo. May I thank the person - not sure if was Bruce - who made the tracks. So often these type of demos rely on the skill set of those who never appear in front of the camera (or the classroom).
HI Empty head, thank you. I enjoy building things so all of the pieces in the videos are pieces that I have built over the years. For those interested I have building plans for most of them
This is a great demonstration, but I feel that the description is incomplete. The explanation makes it seem as though the track that dips converts more potential energy to kinetic energy and that the ball on that track reaches the other side with less potential energy and more kinetic energy. However, to my best understanding, this dipped track converts potential energy to kinetic for brief portions of time which allows that ball to cover more ground, but at the other end of the track both balls have the same potential energy and the same kinetic energy (minus friction and drag effects on the longer track). Basically, at the finish line they both have the same potential energy (because they are at the same height) and similar kinetic energy (because they both started with the same total energy). The only difference is that the ball that dipped traveled faster for brief periods of time--making it over quicker--but also lost some overall energy due to friction and drag.
my hypothesis is that the ball with curves travels faster because when it drops it gets more speed and when it comes back up it loses speed but it has roughly the same speed as the other ball, so it has a higher medium speed...
yup and only unless the next hill is higher then the previous is the only way to loose potential energy, so as long as the hills are the same height and same grade it will gain speed then loose what speed it gained on the next climb and the start over again allowing for a slight speed increase
Someone may have mentioned this but I think it would be useful to talk about vectors in this demo. The downhill portions add to the ball's horizontal velocity, so I think in a frictionless system the wavy track would never be slower than the flat one (as long as the wavy track is always lower or even with the flat track).
"O ye'll tak' the high road, and I'll tak' the low road, And I'll be in Scotland afore ye, But me and my true love will never meet again, On the bonnie, bonnie banks o' Loch Lomond." QED
Just a thought, the track with more lows and ups gets a pull by gravitational force while ball travels down, while in the steady track gravitational force acts to stop the ball and add more resistance to the flow
Proof that taking the low road in life will always get you where you want to be faster than taking the high road. Hold grudges, backstab, and get ahead in life.
I gotta say I did not expect that. I assumed that going back up the hill would cause the ball to slow much more than it did evening out the overall speed so both balls would end up at the end of the track at the same time or even possibly the ball that travelled further to be there after the ball on the straight track.
My screen has a crack so i am not able to see the image clearly but from the comments, i can assure you that the wedding was fantastic. The only thing we are wishing the couple is a fabulous honeymoon and a happy marriage life.
The physics behind it is pretty simple. After the little drop both balls do, they have the same velocity pointed in the same direction. This horizontal velocity will stay the same (only a bit get lost due to friction). If the front ball gets the chance to travel even lower, the original horizontal velocity remains! By dropping down the ball gains extra velocity that is at first vertical but then gets directed by the rail to be horizontal aswell. After raising to the original level, it got the same velocity as the ball in the back (there are indeed some losses because at the "turning points" where the front ball gets directed from down-dropping to horizontal and then from horizontal to raising, there is more friction then normal which results in a higher loss of energy). By adding more bumps the front will always be faster - only if the friction gets to big it will lose the race.
![ลองสั่งของจากแอพ temu ถูกจริงหรอ?? ( part : 1/2 ) [โกงไหมครับ ep.89 ] | DOM](http://i.ytimg.com/vi/RTcZSQTiDZw/mqdefault.jpg)
this Guy has balls of fucking steel
gfd
illuminati guy fick dich
@@ellenorbjornsdottir1166 chill dude. He didn’t say nothing to you
Great observation, Davi 👀
Interesting, I remember using this as my final project for high school calculus.
If we treat the track as a function, the time it take for the ball to travel the track is ROUGHLY the integral of that function (area under the graph). the less area under the track, the faster.(actual velocity function involve square root of the graph, x-axis is distance, not time. t = ∫(dv/dd) )
this also apply if the ball start with some velocity or if the track has loop like roller coasters. Just need to adjust the boundary intervals and treat the loop as piece wise function.
also, we can model the friction use the concavity (or second derivative) of the function, since both of them are proportional to the normal force the ball exert on the track.
Please don't say "rate of speed"! Speed is a rate. It's like saying that something has a high height...
Nicholas R.M. Acceleration
Unanticipated Fourth Dimensional RoboSpider Jesus No he just meant speed. Think he's a bit nervous in front of the camera. Still a great video.
Unanticipated Fourth Dimensional RoboSpider Jesus Also, acceleration is rate of change of velocity, not speed.
There's nothing inherently wrong with 'rate of speed.' it's not like saying a high height; it's like saying 'measure of mass.' A little redundant, sure, but nothing wrong with it. Also, speed and velocity are interchangeable until you choose a coordinate system.
Velocity does not exist without a coordinate system
And people tell me to take the high road
It not might be as fast but it will take you farther :)
That's all well and good, but the low road ball never actually reaches the "end" of the track. The low road will always be faster, but never go as far. So depending on what point you actually assign as the finish line, the high road may be faster in the sense that it is the only one that ever actually finishes.
Kur Norock. Thats a bit of a nonsequitor, as you can also argue that both balls don't exactly make it back to the starting point. What remains is that the extra conversion of potential- into kinetic energy gives the long track a net speed advantage. (Even though it has to again convert that kinetic energy back into potential)
I noticed that as well. The slow motion replay always seems to stop just before the ball on the high track reaches the end so we never get to see if it travels a greater distance.
Joel Dodson. It doesn't travel a greater distance!! In the given tracks, both balls travel the exact same net distance.
The difference is that the ball on the longer track gets more speed from a higher vertical drop. Unfortunately the experiment suffers from friction (on both tracks), which results in energy loss. Friction is proportional to speed (so the faster ball loses more energy) AND on the longer track the friction works over a longer distance (so the ball loses more energy). The energy loss (in both tracks) mean that the balls will come back to a lower point every time.
Dozo G I wasn't talking about when the balls return, I was talking about when the reach the end of the track. The ball on the longer "low road" always stops a bit short of where the ball on the flat "high road" track stops.
Kur Norock. Argument remains the same, except on a return trip the effect is double.
The question becomes: what track shape gives the shortest time for the ball to reach the other side?
Porglit This shape is called a brachistochrone and is made up from a cycloid.
i guess the fastest and lowest drop and fastest ascend, though i did not even try to check the calculations cause i'm too lazy
Porglit the brachistochrone :)
th-cam.com/video/skvnj67YGmw/w-d-xo.html
back when Vsauce still uploaded for us. But yea, the brachiosaurus rex is what you're looking for
The track with 45 degree inclination with one bump
This is a good analogy for life
what is the analogy
At what point do you experience diminishing returns on this? I imagine in the degenerate case of an infinite drop and an infinite rise, no amount of speed could be enough to cover the infinite distance of the dropping track faster than the straight track. So when do we hit an optimum drop distance / track length ratio?
the problem with dropping the ball too far is that it converts some of it potential energy into rotational kinetic energy, as it climbs back up this energy is needed to be converted back to potential again to get the ball to the top. If I make the track too steep, the ball will lose traction and can't make the climb. I find this to be the limiting factor so theoretically the ideal distance for the drop may be different that what will actually work.
If you're interested in the answer on where to expect diminishing returns on the case where the rotation of the object can be ignored, look up the brachistochrone problem, which is the name for this question in classical mechanics. (Spoiler: the most efficient path is a cycloid.)
just to be a pedantic jerk....you didn't specify "in vacuum" so you'd hit diminishing returns pretty quick approaching terminal velocity.
Also due to air resistance, after reaching a certain speed (Terminal Velocity), dropping down further won't not speed up the ball.
Zekian
Hmm, but let's ignore for the moment friction. Neither ball rotates as it slides down either track, and there is no air resistance. The question I'm asking is about the speed gain from the potential/kinetic drop/exchange versus the cost of making the path longer. Was that the cycloid answer from before?
Reminds me of the brachistochrone problem. Cool video, your students are lucky to have someone who has such a knack for making non intuitive results as easy to understand as possible.
thanks, the next one will have it
Bruce Yeany That would certainly be interesting to see. I think you'd enjoy some of the videos by 3Blue1Brown, they have a knack for approaching various mathematical problems in ways (often geometric) that give additional insight into how everything is interconnected, such as how the brachistochrone can be solved using both Snell's law and as the path of a cycloid, or how the solution to the Towers of Hannoi is the same as binary counting/the path through a Serpinski triangle for the constrained version.
thanks, I will try their site
@@YeanyScience No different than a gear or pully... the slower ball actually travels further each time on each end, if you look closely, the balls aren't actually traveling to the very end and not to the same length at the end points... The one with the curves is like the big sprocket on the back wheel on a 10 speed and the straight line is like a smaller sprocket on the back of a 10 speed. The two balls are also spinning at a different rate so the Torque is also different. The curved path provides more torque and can't make as close to the end-point, but the straight path has more horsepower and goes further up toward the end-point. Since the energy must be conserved, the straight line ball trades going further toward the end-point with a slower time, the faster ball trades a faster time with going less toward the end-point. Interesting experiment. If you changed the diameter (and even the mass distribution) of the ball you could fine tune the speeds and how far up the last incline each ball went... you could get very close to no improvement in speed by using balls with less or more diameter in comparison to the design of the tracks... one ball is traveling further and higher (more distance up the end-point) and has more force, but doing it over more time... while the other ball is traveling less, and lower (less distance up the end-point), but doing it faster... so all that is change is time, it's a sort of time dilation.
It is practical lessons like this that keep me interested in both physics and math.
thanks LOrd
Great experiment, but you really should have a gate that holds each ball and drops them simultaneously.
Good idea, thanks
Mr. Tangent yes technically to fully go with the scientific method and eliminate as many variables as possible, he should have. but u can see that he started giving the straight line ball a bit of a head start to prove his point. I think the experiment serves its purpose just fine.
Cool Demo - I'm pretty sure that what you've demonstrated is a principle in many Air Combat Maneuvers (such as the rolling Scissors)
wow, if it is, that's pretty cool, thanks
I actually use a path like track two in War Thunder to catch up to bombers since you accelerate quickly to your top speed and then end up able to open fire from directly under them while still having enough energy to escape most of the return fire.
The aim of rolling scissors is to reduce the closing to the bandit so you can stay behind his 3/9 line (while he does the same, so you both end up doing this kind of barrel roll around each other). I guess you mean that this experiment would be more similiar to a lo-yo-yo, where you want some closing into the bandit.
Jose - you are indeed correct Sir! I was think of the hi and low yo-yo!
The maneuver that I was describing is only valid if you are well below top speed and are at an equal or greater height to the target. It brings you to top speed quickly, and puts you in a good position to attack. You just have to make sure you wont pass low enough to get in any enemy fighters range on your way to the target.
Nice demo. Slight correction You say the track lengths are the same. Both I think what you really mean is the horizontal distance the ball travels is the same for each ball. If there are any scouts who participate in the pinewood derby this is a really good lesson for them.
thanks, I messed that up. It's not always easy being in front of the camera
Bruce Yeany We all make mistakes.... This was a good demo. Did you make all of these?
Passed High School Physics where I'm from for the pinewood derby the track is equally for everyone so it comes to the aerodynamics of the model
Nathaniel Schmitt How or why do you think it comes down to aerodynamic? If you think about it aerodynamics has almost very little to do with it at the speeds pinewood derby cars race at. This is a great example of where math would give away the answer. The Drag equation even proves it.
It turns on there are really only two factors in determining which car will win. Friction and PE.
Fiction plays a big part in which car will win. There's frictional drag from the wheels rubbing against the side of track and and then there's the friction from the axles.
What's being demonstrated in the video is just as important too. Too bad the teacher didn't explain the energy math. The math would explain's it perfectly. it. Not sure if you took physics, but if you had you would have learned about PE and KE. Just to refresh PE=MgH and KE= 1/2 MV^2,
Ignoring friction and look at he PE. Just like in the video. Looking at the KE one would expect the car with the highest velocity to win.
Here's something to think about. If you have two identical derby cars. Same weight, same aerodynamics same frictional forces how is it one car can have more PE and win every time? (This is the secret.of how to win.)
This was fun. We used the sum of potential and kinetic energy in mechanics problems all the time, yet I've never seen this concept demonstrated like this. It was very pleasing to see just how clear the results were.
but you can also see that the one with the slopes doesn't go as far up the return slope. meaning in theory it isn't actually traveling the full distance. maybe a small Tiddle to think about.
If you would make the tracks the same length, they would end up at the same height. Now the ball in front travels a greater distance, so it experiences more friction, thus it doesn't reach quite as far back up.
EdwardtheIRISH only because of air resistance and friction though
Why I loved science teachers like this. The things they built to show science were simple yet well measured and built. The mess of bulletin board patchwork behind him is great since this guy is obviously capable of decorating with precision instead of chewing the paper apart. Learning tool or pretty decor? Easy to tell this guy chose to engage around his subject and knowledge instead of making his room feel fancy. Nothing against the pinterest mafia but this guys prep time is well spent.
but which ball will come to a complete stop first?
good question, I don't know
If everything else were equal the only difference would be the actual distance between the two tracks.
If both spheres start with the same energy, they should both be able the same overall "distance".
I believe they might actually stop at the same time.
But the one with the hills may stop first since it travels faster at points, expending more energy over a shorter time.
If you still have the setup I'd love to see it. Maybe fast forward a bit.
I still have them and will give it a try on all of them and see what happens. they are at my school so it will have to wait until Monday
The flat surface jas a constant friction, it can use up all potential energy as kintetic energy.
The one with the hills have a peak which requires alot of energy to overcome, at some point it has enregy left, but not enough to travel over the hill.
It will waste energy and therefor traveldistance.
That is at least my hypothesis
Bruce Yeany
You are the best
if you look closely, the shortest path allows the ball to actually move up the end ramp and start ramp, on its return, a little further. This is expected since there is less irreversible energy loss (sound, friction) on the shorter path. This concludes that you can actually get more work done with the shorter path ramp since it has more momentum at the ends.
The paths are not the same length, they just displace the ball the same net amount
SamBskate
He never said that the paths are the same length, he very clearly said that the straight path is the shorter path.
AERO BLKHWK32
0:18
SamBskate That was the first thing that struck me when I started watching the video. Those two tracks are NOT the "same length"... the one that is closest to the camera, clearly has a longer surface area for the ball to traverse than the piece of track that is closer to him.
+Keith Mathews yes the ball has more distance of travel due to change in elevation but both tracks begin and end in the same distance
Alex Thatcher ... The gentleman in the video said that the length of the two tracks were the same, and they are clearly not the same. But, in order to put an end to this debate, we must agree that we disagree :)
that would explain why I prefer bicycling on rolling hills vs flat roads.
All I know is from 10's of thousands of cycling miles, I can build up quite a bit of speed on the downhill, and generally carry it to the top of the next before sitting down again.
Where's riding across Kansas was pure torture.
I realize the equation us mire complicated, by the feeling says it all.
Actually Emmanuel, that shit would work. You see as long as the frictional force is compensated at the top of the hills and Visfor doesn't eat shit on pavement, he should be able to travel a longer distance because he has sections of high speed and almost no work.
it ll only work till the peaks are at lower level than the starting point...the additional energy the balls are getting due to higher potential energy is converting into KE... once the peaks get higher than intitial point...the KE ll b convert onto PE with some loss in energy n the ball ll slow down...so it depends on the hills
In terms of speed, hilly road is better than a flat road.
In terms of effort, expended energy, they're both similar.
***** you've never ridden across Kansas, have you?
Great video. Love to see science promoted on TH-cam!
Too Much Thought love to see all the retards in the comments section asking high school level questions that they could just Google.
Michael Faux hey, nothing wrong with High School level questions. This isn't a college level course.
I do grant they could google it, but that does mean they should. I don't think they are "retards", maybe just a little lazy for not looking it up themselves. Still they could be watching Minecraft or react Videos. I'd say that hostility to people who are wanting to learn won't help anything.
Science? Seems like physics to me.
TIL Physics isn't a science
AllTimeIndie But it is a branch of science 🔺
really nice! I can't wait to show it to my kids tomorrow :)
There is a competing principle where the faster ball experiences greater drag (loss of energy) because drag is proportional to velocity squared. At these low speeds however, its a minor factor to this outcome.
I think the misperception that we get when we originally look at the scenario is that the extra drop and rise would cancel itself out. A very interesting video
The tracks are not the same lengths. Just saying.
Edward Bernard that's the point the ball on the longer track still gets there faster
Hitch Slap no he is correct. Strictly speaking, the low track is longer.
Hitch Slap I agree with you, and if you think about it, the low track covered a longer distance in a shorter time, so it's even more impressive
Hitch Slap but he does have a point.. The track is longer
...but not as long as this video.
very cool. Im starting another year of chemistry and seeing visuals like this to explain the topics before I start are always fun.
Is a physics teacher.
Uses the term 'rate of speed'. :/
lol yea but he did say in a comment he teaches to 7th and 8th grade so generally the way he would speak and the terms he would use for the younger people would tend to become habit.
michaelhladun7
What's wrong about it?
Nicholas Hartle its called velocity
The fact you still knew what he was talking about makes the choice of words irrelevant. If you knew what he meant, even slugs will understand.
All words are made up.
Also "heighth" (I mean come on)
As a skateboarder, this is extremely relevant to me. 10 thumbs up.
great demo! i would also point out thst the longer pth the ball did not go back up as high because friction
a cool little addition is that at any point that the two balls are at the same height, excluding loss of speed from friction, they should be moving at the same speed. It would be cool to create a track that is even in the front and back at the middle to show this. also, adding curves is kind of like calculus. if you were to add infinitely many drops to the first track, it would begin to behave more and more like the 2nd track. (sorry if you already pointed this out)
You look like such an iconic teacher. With the hair, the outfit and the mannerisms, you're the avatar of male teacher.
Wow, thanks
This is some revolutionary science. Who would have thunk it that bursts of acceleration would beat non acceleration.
gravity....it's always bringing me down. 🙁
Gravity... its always converting my potential into kinesis.
Gravity opposes to my height increment
I don't know how this came into my recommended videos list... But at least I learned something new which is more applicable irl than calculus. Thanks!
Idk why but this is pretty awesome when you're stoned xD
thanks sir i appreciate you dedicate time to show and teach about to those of us who wander all day on youtube
really, thanks
Good video, although "Rate of Speed" is pretty sloppy. Cheers, Si.
Very interesting video. Thanks for sharing. Wow, I just took a look at some of your other videos. Great stuff. Subscribed.
thanks
I just watched your "Solar motor--Free energy motor" video with my three boys and we all loved it. I will probably try replicating and enhancing that design and see if I can get it to power a small generator. I have also learned that the term "free energy" means different things to different people. I have always naturally thought of things like solar energy and atmospheric electricity as free energy sources but under some folks definition nothings is "free". Anyway I know how much work making videos is and I really appreciate your content. My boys are already flying magnus effects cups around the house.
excellent!! if you want instructions for building, send me an email address and I will forward them to you. I have a quote on my wall that sums up my mind set, Sunlight is free until the government figures out have to tax it. My idea of "free energy" is tapping into ones available without costs.
Real world science is cool. Practical application and explanation of potential / kenetic energy interaction in your demo was excellent.
The high road ball always wins - marginally. Watch closely and you'll see that the low road ball in each case doesn't go as far up the ramp on the far side.
mjribes
Okay, but where is the finish line?
He's making a point that both tracks have both ends at the same height. Or as he wrote in a comment: "I did carefully pick the height of the humps, they rise to the same height as the high track but not higher." So the "finish line" is the end of the track.
I find it noteworthy that he makes it impossible to see both balls slowing down on the way back every time, either by stopping the recorded video before the slower ball gets back, or by picking up the faster ball before it slows down to 0, while letting the slower ball roll to the end.
I can only conclude he's doing this intentionally, because he does it every time. If he would let the balls roll until they don't roll up anymore, the faster ball will actually stop sooner due to friction, since the curved track is longer.
I disagree. The ball on the up-down track will "finish" in a trough.
Walter W. Krijthe He's stopping the balls intentionally but not to cover up the fact that faster balls will lose significantly more energy due to air resistance increasing (as another said, 4x per 2x speed), or that longer tracks will create more friction. He's simply making the point about the conversion of vertical potential energy into lateral kinetic being more time efficient. It might be energy inefficient, but that's not what he was describing.
What is with this kookery? That everyone thinks all others have a secret agenda to manipulate their world view via fucking basic physics.
omgcow & Maxx Kroes, you both take more offense than Bruce Yeany. He replied to my comment on the video about 2 weeks ago.
awesome demonstration, I wish you were my teacher in high school!
I still don't get it
The PE generates more KE on the second track, but shouldn't this surplus of KE be consumed for lifting the ball up the hill?
I mean, I expect the ball to have higher speeds at the downhill, but lower speed (than the other ball) at the uphill so they compensate
can anyone explain this to me?
chromme it spend the strait section at sutch a increased speed than the other ball it does not hage time to catch up
chromme the balls have the same PE, but the key is that during the period when the lower ball has a higher KE, it is covering more ground at its higher speed, and the ball with constant KE never makes up that difference. So at the end of the track, the balls are going the same speed, in the low portions, the lower ball is at a higher speed
chromme ok, the faster moving ball over a distance, can get enough of a lead that it doesn't matter that it slows down going up. if the tracks were extremely long and there was friction/air resistance, the faster moving ball would have an even greater lead. So it really depends on the length of both tracks. If the track was short enough, then yes the paths would have the same completion time (the track would have to go down and right back up).
chromme you don't get it because PE and KE don't exist. They are made up.
if you imagine it to be an ideal system, than the second ball will start going faster when it falls and when it ascends it will just "reset" to the speed of the "normal" ball and it will not ever go slower than the first ball thus making it faster overall. this one is not an ideal system but the friction is low enough to see the effect.
This was pretty cool and quite counterintuitive too at the beginning.
ah, so that why if you take the high road and I take the low, I'll be in Scotland before ye.
This makes me think of the types of path we take in life... you can cruise or live with great velocity.
im 25sec into this video. They arent the same lenght.
You’ve designed the track for a specific outcome. The harder design and the better lesson would be having the balls finishing simultaneously in my opinion. I appreciate your time and effort to make this.
actually they are diffent lengths . the linear distance from point a to b is the same
Thank you captain obvious.
Thank you Bruce. Awesome as always.
You have way too less viewers for your great channel - at least you have a new subscriber and fan now. :-)
Thank you for the nice video.
HI lupuszzz, thanks.
Agreed. This channel is one of my favorites
Fascinating, I was seriously stumped for a while but your explanation makes perfect sense 👌
Why does the ball on the straight track consistently end higher on the up slope?
carl witt it doesnt lose as much energy due to friction so it can convert its extra kinetic into more potential and make it higher up the up slope.
carl witt it is not traveling as far so the time it spends being slowed by friction is less. Therfor when it reaches the other side it has more energy. This is why roads are flat not a set of hills flat roads conserve energy. Hills consume more but have higher acceleration in the first slope.
All of my roads are hills. Flat roads, now your just telling stories :)
Bruce Alan to be fair i live in eastern alberta
Now this is how all teachers should be
Misleading?
I just can't pay attention with that outlet being upside down...
Pseudo Mortality in the Electrical code, any receptacle with a metal faceplate must be positioned with the ground prong up. This prevents a short circuit in the case that the faceplate were to fall off, as the faceplate would only touch the ground prong as opposed to bridging the hot and neutral.
kwizzy902 you're totally making that up, but I like it.
Wow that is amazing that the wall outlet is upside down usually showing that it is a half hot outlet! One receptacle would always be hot and the other would be operated by a light switch. Amazing! Oh and I loved your video. being a Sailplane Pilot I use this technique all the time between thermals and porpoise fly as much as I can.
The straight line track is just the low track as the number of hills approaches infinity.
Twelve Seven I knew there'd be calculus in there somewhere. I was thinking that the times would be the same if the average heights were the same. What do you think?
I think then it would depend which had the overall shortest length track.
When the number of hills approaches infinity there'd be a point where the ball is too big to fit into the valley an get stuck.
Yes, but that would be at a rather small fraction of infinity.
Actually, it will just roll over the tops, never touching the "valleys."
A variation on the theme: if the "low road" climbed above the high road for a moment, what then?
Alex Snitzer by the looks of the balls and I think because of some laws of physics, there is no possible way the ball could climb above the other one of both start at the same height
That's not what I meant. If the "high road" dips lower than he has it here, the "low road" can have the hump I described and still make it over.
Alex Snitzer O MY FUCKING GOD. YOU'RE ON THE INTERNET, LOOK UP BASIC PHYSICS. facepalm facepalm. You have a potential energy at the start, that translates to a maximum kinetic energy at the midpoint, half the distance from peak to peak of an even curve. so you come back up to the starting point.
Alex Snitzer here is a simple test for you. Take a bowl, release a marble from the rim. note that it doesn't jump out of the bowl, it just goes up and rolls back. it doesn't have the energy to make it higher than the STARTING POINT. Really simple.
Alex Snitzer opposite. It would slow down
this is a good example of gravitational potential energy, rotational kinetic energy and acceleration of gravity.
So, our highways should be bumpy instead?
Cars are driven by engines, we don't push them off the top of hills.
No, the energy in both tracks is the same at the end if you don't consider friction
If our roads were dipped like the track we would be traveling extra distance, resulting in:
more distance that air can drag on the car,
More energy lost to friction in the drivetrain and tires
Speed limits regulate max speed anyway, meaning we cannot utilize the PE to KE conversion displayed here
Markus Andreas no because the the energy used to make it faster is taken from the energy to make it travel far. So you might me going faster than a flat road but you won't get as far
So if you are flying a single engine plane and lose your engine you find the perfect glide speed so you can glide the furthest distance. Would this concept apply to aircraft as well? So instead of finding the optimal glide speed, try to make the plane climb and fall 100 feet at a time, making the plane go faster extending its glide distance potential?
You are misunderstanding something here. The ball on the "lower"/wavy track goes faster, but both balls have the same amount of initial energy. If he were to let the balls go back and forth until they both eventually stopped, you would find that the "lower"/wavy track ball stops first. But if you were to measure both tracks, you'd find that both balls traveled more or less the same distance overall; one just uses its energy at a faster rate. As for your question about the plane, the more important "distance" is distance measured across the Earth rather than the actual distance the plane travels. Thus, the optimal glide speed is going to end up with far more Earth distance than a wavy track would; though the plane would travel the same actual distance regardless, the glide distance in comparison to the Earth would be far more if the line was straight.
rumanenough wow! Great response. Thanks. You cleared up my confusion 100%. This makes so much sense.
Crazy Nate Also, this wouldnt be a good move because the velocity would change depending on position in the "wave", faster on the bottom of the wave and slower at the top, meaning that absolute optimal glide speed couldn't be achieved all of the time unlike in straight motion.
it worked for Mario when equipped with a cape.... must be true. Science!
you must like to play with wood case you need a good band saw to cut all that out
Hey Clay, I've got some good but modest set of tools and what I can't do at home, I was able to complete at our school using the wood shop
the lesson that we can learn is, in this life if we got so many problem just believe its increase your speed for your goal. but if you just got a straight way or flat way maybe be you just in cozy place, because life is never flat.
1st of all they arent the same length
the lower path is inches longer
very neat visual
Thank you captain obvious.
why did this video go from almost no views over 2.5 years to a HUGE spike this year? great video!
I have no idea
the two tracks are not the same height, the straight one has a much lower ball release height, if you made them truly the same the result would be much different.
the height of the track is determined by its lowest part NOT at the physical point of release, following your model you could have a 60 foot drop covering the same distance and as long as you line up the start point you would say they were the same height.. your experiment is flawed.
Gail Raby the end point is the same height and so is the start so the potential energy and kinetic energy in both balls is the same at the start and end
+ThePizzabrothers Gaming
not true, you clearly fail to understand what you are doing.. YOU DO NOT HAVE THE TRACKS AT THE SAME HEIGHT.
the actual height it's travelling at has nothing to do with the end result, it's about the journey to that height. and your example of "following your model you could have a 60 foot drop covering the same distance and as long as you line up the start point you would say they were the same height" makes no sense; the END point also needs to be the same height.
+ThePizzabrothers Gaming
I am not about to explain where you are wrong but wrong you are..
the two tracks are NOT the same height, the flat track has half the drop of the other.. that alone explains the difference in speed...
THAT'S THE POINT OF THE EXPIRIMENT
One thing not mentioned here is how the rotational energy from the balls affect this experiment. The increased rotational speed of the lower tracks allows it to travel back up the hill without losing as much kinetic energy. Try to on a track that doesn't allow the balls to rotate and you'll get different results.
This is great video. This is simplest visualisation of gravity assist.
i need to make 1 of these, could watch it all day lol.
no plan you have no life?
Many nice!! , i am from Brazil! thanks for your post!!
I have a question. The "low road" ball speeds up going down hill due to gravity (potential energy turning into kinetic energy), but it also slows down going back up hill (kinetic energy turning back into potential energy). Why doesn't the down hill and uphill actions cancel each other out?
Because it is traveling the lower most part of the track with higher speed than the other ball
If I were to think of this as a graph, where the flat track is the zero axis of Y, then every drop below the Y axis would equal an acceleration along X. Therefor the only way to cancel out the acceleration is to make the lower track rise above the Y Axis. This is a great way to understand the relationship between Potential energy and Kinetic energy.
Don't know if you have tried this, but if you made one end of the track horizontal on each, the balls could then act as projectiles and should travel the same distance horizontally before hitting the floor. That would demonstrate that they had the same KE at the end of the track since they started with the same PE at the beginning.
Reminds me of the calculus days. Now I'm a chemist/geologist but nonetheless a useful video as a cyclist/skateboarder.
This video is life changing. Imagine the tracks as your life and the humps and dips as your struggles.
you would eventually get to a point where its kinetic energy stops increasing and the straight track would win, albeit you did prove it would take quite a distance. fascinating video, if i could take a physics class again i would
Love the experiment, always cool to see these ideas in real life. Just one thing. You cannot have a "rate of speed" for two reasons. First off, "rate" has to be followed by a "change" word (eg. rate of increase/decrease/change)(unless you're talking about something being priced at a "good rate"). The second is that speed is a word for a specific type of rate - that is distance over time. Saying "rate of speed" is like saying "the rate of the rate."
you should build one in which the lower track is a parabola shaped such that the balls do arrive simultaneously. It would have to sit on the edge of a table to accommodate the low track but other than that there really shouldn't be any feats that go beyond a few simple calculations.
Awesome. Loved it.
Great videos. Thanks for sharing !!!! greetings from Colombia!
thanks
cool to see! it would have been nice if you also explained that the balls have equal speed when they are at the same height though, and you could have also shown us which one experiences the most loss in energy over time (im thinking there are multiple reasons for the more bendy and longer tracks have more energy loss).
I like your videos...want to point out that the low road is the hare and the high road is the tortoise ...same energy farther distance...eventually the hare takes a nap while the tortoise keeps on going
I love all your videos man they are really creative in my opinion.
Excellent demo. May I thank the person - not sure if was Bruce - who made the tracks. So often these type of demos rely on the skill set of those who never appear in front of the camera (or the classroom).
HI Empty head, thank you. I enjoy building things so all of the pieces in the videos are pieces that I have built over the years. For those interested I have building plans for most of them
Great project, how can I obtain a set of plans? What did you make the track rails out of?
This is a great demonstration, but I feel that the description is incomplete. The explanation makes it seem as though the track that dips converts more potential energy to kinetic energy and that the ball on that track reaches the other side with less potential energy and more kinetic energy. However, to my best understanding, this dipped track converts potential energy to kinetic for brief portions of time which allows that ball to cover more ground, but at the other end of the track both balls have the same potential energy and the same kinetic energy (minus friction and drag effects on the longer track). Basically, at the finish line they both have the same potential energy (because they are at the same height) and similar kinetic energy (because they both started with the same total energy). The only difference is that the ball that dipped traveled faster for brief periods of time--making it over quicker--but also lost some overall energy due to friction and drag.
Se te complicó a lo último Bruce pero quedó clarísimo.. Sos un genio!
give this man a raise
my hypothesis is that the ball with curves travels faster because when it drops it gets more speed and when it comes back up it loses speed but it has roughly the same speed as the other ball, so it has a higher medium speed...
and it's proven in 3:20 that the ball doesn't slow down to a slower speed than the other ball
yup and only unless the next hill is higher then the previous is the only way to loose potential energy, so as long as the hills are the same height and same grade it will gain speed then loose what speed it gained on the next climb and the start over again allowing for a slight speed increase
Someone may have mentioned this but I think it would be useful to talk about vectors in this demo. The downhill portions add to the ball's horizontal velocity, so I think in a frictionless system the wavy track would never be slower than the flat one (as long as the wavy track is always lower or even with the flat track).
This is great! Thanks!
Nice, now let's make all the roads like this :)
I've seen a few of your videos. Keep it up, you're a great hands on teacher.
thanks Chris
"O ye'll tak' the high road, and I'll tak' the low road,
And I'll be in Scotland afore ye,
But me and my true love will never meet again,
On the bonnie, bonnie banks o' Loch Lomond." QED
Just a thought, the track with more lows and ups gets a pull by gravitational force while ball travels down, while in the steady track gravitational force acts to stop the ball and add more resistance to the flow
Proof that taking the low road in life will always get you where you want to be faster than taking the high road. Hold grudges, backstab, and get ahead in life.
I gotta say I did not expect that. I assumed that going back up the hill would cause the ball to slow much more than it did evening out the overall speed so both balls would end up at the end of the track at the same time or even possibly the ball that travelled further to be there after the ball on the straight track.
My screen has a crack so i am not able to see the image clearly but from the comments, i can assure you that the wedding was fantastic. The only thing we are wishing the couple is a fabulous honeymoon and a happy marriage life.
thank you! That was very informative!
Good educational videos.. I like this channel..
Physics is fascinating isn't it
The physics behind it is pretty simple. After the little drop both balls do, they have the same velocity pointed in the same direction. This horizontal velocity will stay the same (only a bit get lost due to friction). If the front ball gets the chance to travel even lower, the original horizontal velocity remains! By dropping down the ball gains extra velocity that is at first vertical but then gets directed by the rail to be horizontal aswell. After raising to the original level, it got the same velocity as the ball in the back (there are indeed some losses because at the "turning points" where the front ball gets directed from down-dropping to horizontal and then from horizontal to raising, there is more friction then normal which results in a higher loss of energy).
By adding more bumps the front will always be faster - only if the friction gets to big it will lose the race.