Friction - Physics 101 / AP Physics 1 Review with Dianna Cowern
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- เผยแพร่เมื่อ 3 มิ.ย. 2024
- Lesson 6 (Friction) of Dianna's Intro Physics Class on Physics Girl. Never taken physics before? Want to learn the basics of physics? Need an AP Physics 1 review before the exam? This course is for you!
Exercises in this video:
Problem1: The coefficient of friction between your car’s tires and concrete is 0.7. Your car’s mass is 1000kg. If you slam on your brakes and the tires lock, what is the magnitude of the sliding friction force acting while you slide? What is your acceleration?
Problem 2: You put your cow on a ramp. Moo. Then you tilt the ramp up, slowly. Just when your cow starts to slide, you measure the ramp angle as 34º. What is the coefficient of static friction between the cow and the ramp?
Thank you to atrophysicist Naomi Rowe-Gurney for her awesome shoutout at the end of the video! You can follow her on Twitter @nrowegurney
Credits:
Dianna Cowern - Executive Producer/Host/Writer
Jeff Brock - Lead Writer/Course Designer
Laura Chernikoff - Producer
Victoria C. Page - Video Editor
Sophia Chen - Researcher/Writer
Erika K. Carlson - Researcher/Writer
Hope Butner - Production Assistant
Levi Butner - Videographer
Lauren Ivy - Set Design
Vanessa Hill - Consulting Producer
Aleeza McCant - Illustrator
Rachel Allen - Illustrator
Consultant - Kyle Kitzmiller
Lucy Brock, Samantha Ward - Curriculum Consultants
Cathy Cowern - Transcription - วิทยาศาสตร์และเทคโนโลยี
I gave a like for the pun right at the beginning: “I’m inclined to agree with them.”
TBH, nobody cares.
I love how informative and fun this show is
Yes, these videos even help me understand physics for my university physics class.
actual physics 101: "forget about friction, it makes the math too difficult"
Really? High school non-ap physics made me calculate the coefficient of friction by measuring at what angle a penny will slide down the cover of a book
@@empichel5690 sounds like a one day lab just to prove friction still exists type deal
"31 year old child" 😂
Lol
MATH QUESTION
Geometry fun problem
th-cam.com/video/4dkOeJXWDW4/w-d-xo.html
One time see.
ME LIKE: WAIT WHAT?
If there is one positive thing about having most schools go online is that there will now be an archive of educators like this that students can use forever to learn these topics.
Like books? (which are not 10 minutes long).
@@nineball039 Books are great but there is something added to the lesson by watching it in action.
@@Paul_Ch52 A lab exercise where students actually do the experiment and measure the results would be even better.
As a construction worker working in roadwork I couldn’t get over that every time you said a car on concrete you showed a car on asphalt. But I love the videos!
Diana: * Literally just draws a square *
Diana: It's a beetle.
lol
You mean it wasn't?
@@Paul_Ch52 I mean if it's good enough for Diana, it's good enough for me. Lol
I'm not studying physics or anything else, I just like the way Dianna explains things. Looking forward to the next video😊
The friction of sharpie against the paper stimulated 50% of the nerves in my upper body.
First thank you. As a 51 yr old I love learning this stuff, just wish I had any teachers, who made it this easy to learn. Thank You again.
"31 year old child" MOOD!
Really?
Killing it with the pink jumpsuit!
That car drifting wasn't locking up the wheels. It's actually the opposite. The wheels are over-rotating and breaking the friction between the tires and the pavement in order to slide along the surface. But it looked cool.
Hi! I just wanted to say thank you so much for making this series. I came back to your channel after I started taking AP physics because I was really struggling (I used to watch you as a kid). I remembered you're the one who made me love physics and these videos are really helping me understand the concepts so thank you!
So the study of slippery stuff is Science Friction.
This lecture on friction is so smooth....
Your daughter: Why do things feel rough?
You: Because their surfaces are bumpy.
Your daughter: 2:47
MATH QUESTION
Geometry fun problem
th-cam.com/video/4dkOeJXWDW4/w-d-xo.html
One time see.
I love physics, I love this channel and I absolutely love Diana. What a perfect personality for teaching this stuff. If more teachers/professors where like you Diana, there would be more smart people in the world.
I love all Physics problems...I totally agree when you say "we learn Physics by doing exercises". The theory up to high school is pretty easy to understand. Most students think because they know the theory they know something. We actually learn Physics ONLY when we do a BUNCH of exercises. There are so many tricks and tools and ways to putting the theory that a single theory will never do the job of making any student learn much....I love your videos !!! So funny and so correct !!! Keep giving people this high energy... 👍
Amazing. I love these drawing/tutoring-type videos. Hope many more are coming.
Kudos on your science communication. I remember back in freshman physics how clear as mud the instruction was (even worse than in HS physics). Your presentation sort of reminds me of what Jaime Escalante said (paraphrasing to change STEM streams): "Physics need not be made easy; it is easy already." (Well, at least until you start diving off the esoteric high board.)
Your videos are inspiring! Very engaging way to explain to what we take for granted everyday! Thank you Physics Girl!
Love the way you are able to hack into everyone's brains and make them understand the concepts of physics ❤️
I've been waiting to see Mac's part since Andy sent you the footage 😅🤩
And although I've learned already all this stuff, it still so fun to watch! I'm so happy for all students that study physics and come upon your videos 😁
Its so crazy after taking a physics course your videos have been so much more enjoyable bcs i actually understand whats happening
I am involved with practical measurement of friction in a technical environment. An important thing to remember is what you mentioned at one point: Friction is messy. mu is nowhere near the constant for which it is introduced in high school physics.
A famous quote of our lab engineers when you order measurement of a coefficient of friction: "What value do you want?"
It depends on lubrication, on aging of involved materials like rubber or oxydation of metal surfaces, on ambient conditions like temperature, humidity, vibration, on speed, on pressure (even if the straight up Coulomb theory say it doesn't).
So one thing to absorb: Yes, you can calculate with the law of Coulomb. But there are significant error bars on those results.
I love you Diana! (Platonically of course!) You have a fantastically engaging way of teaching!
Fantabulous video. I was hooked on this one, and I almost forgot that I was "learning" or "taking a class" because it was so fascinating. Good explanations! I am especially thankful for the series of "why?"s about "why" is there friction? Because the molecules are trying to align and bond and link up. Now I know! Thank you!!
I always knew Physics Girl AKA Diana should do some physics explanation videos, or tell us about science, because she studied physics so much and her enthusiasm is so great, but sometimes in her earlier videos she skipped the nitty gritty fundamental physics details. This series is exactly what I was looking for, thank you again!!! Shout-out to all the crew and researchers who make sure the info is good and think of cool ways to explain this! And whoever's idea it was to demonstrate coefficients of friction with ice blocks in the beginning! Definitely made me curious "okay, how does this really work? It's the same hill, the same person, all that changed is the ice..."
I am in love with these videos..... ❤️
Thanks for all these efforts.
Also thanks for the production quality of these videos. ♥️❤️♥️❤️
I just started watching and I know I love it.
The link between static and dynamic friction and intermolecular forces was quite interesting. It makes you really think about static friction as a macroscopic manifestation of the molecular stickiness but I still think there is an intermediate microscopic scale where it is mostly due to the rough surface and jumping over the bumps without getting trapped inside holes if you are going fast enough. The molecular stickiness is probably a dominant factor only on very smooth surfaces.
Excellent, young lady. You're doing well in this new role.
THANKS DIANNA I NEVER UNDERSTOOD FRICTION BUT NOW YOU MADE IT SO CLEAR !!!
So grateful for this series
I'm a simple man... I see a new video by Dianna (Physics Girl) and I click & watch!
Thank you so much for this video!!! You make physics really fun😁😁😁👍🏻👍🏻👍🏻 I love how enthusiastic you are when it comes to physics
Thanks for another video for Intro Physics Class :)
Good vid., enthusiasm, clarity and passion.
Hey Diana I have that book too!! Sean Carroll is good at making ideas easy to understand
Your way of explanation and your expression both are very nice, which I most like
This is a pretty great video! Great explanation about friction. 👍🏻
Nice video, as always. Just want to point out that at 10:20, the formula given is for maximum static friction, not static friction in general. Static friction can be as small as 0 when there is no tendency of relative motion between 2 contacting surfaces, and it can be as large as the product of static friction coefficient and the normal force when the relative motion between the surfaces is about to start. Imagine a book resting on a table. When there is no horizontal force on the book, the static friction is actually 0. When there is a horizontal force applied yet the book remains stationary on the table, then the static friction must be equal to the applied force but in opposite direction so the net force on the book is zero. But if the applied force keeps increasing, eventually the book slides on the table because the force exceeds the value of maximum static friction and the static friction on the book can’t increase beyond that.
If my physics teacher had been anything like you I'd have nailed physics a long long time ago!
Phrasing!
Like always another great amazingly educative video
There is the static and the dynamic friction forces which don't depend on the area, but there is also adhesion (caused by van der Waals forces) which is proportional to the contact area. With just friction an ant couldn't climb up a wall without anybody pushing against it like you did the book and a Formula 1 car wouldn't need wide tires to go really fast around a curve.
Hey Diana great videos. They are helping me pass my first physics exam! :p
Little point though for the first diagram of the car.
At the start you write a velocity, a force that on this flat plane, directly opposes friction. Yes?
But then you calculate the sum of forces and ignore any force from V (velocity)??
So I had to sit here, replaying that section and figure out what you were doing. And Sum of forces I always stuff up, so it was confusing!
My thoughtful tip -->
Perhaps if you write a diagram and include a variable, in this case V, maybe either mention ignoring it as you calculate or just don't write it. Especially since you summing forces but don't do anything with it. IE Maybe wait on putting it in until you recalculate Kinetic friction perhaps?
Anyway, don't know if you'll read this but thanks for all the videos!! :D
Nice video, only one remark, if you find it interesting ;) 15:31 In a free body diagram, the direction in which you draw an arrow defines the direction of that force. So actually the minus sign doesn't belong there, because the arrow already points in the negative direction (assuming the coordinate system is defined as usual) It would be different if the force was written as a vector, because then the arrow is only an indication that there is a force with some direction.
Excellent work.
Hi Diana. An explanation of “wringing gauge blocks”. It would be interesting to see your take on it scientifically. Thanks.
Nice explanation. Include photos of sand dune etc which have same angle irrespective of size. This angle is different for heaps of different materials.
You can pour slowly and show how it grows and explain.
I needed this during my highschool years!!! 😭😭
I always liked physics, but I hated math in school so in college I studied English. Since Starbucks doesn’t really pay the bills, I became an electrician and all the math I was avoiding came back. It’s amazing how easy mathematics can be when you have a practical application for it. Now my interest in physics and that hated math have come together to aid me in my career. No matter what you do, a basic understanding of how the universe works can be a very helpful thing (there were even some things that were easier at Starbucks with a basic understanding of friction).
A cause of friction: What a tight and shapely explanation!
Did I miss the joke??!!? There is only one way to end a lecture on friction:
Q. Two cats are sitting on a roof. Which one slides off first?
A. The one with the smaller mu!
God NO!
What does µ have to do with cats though?
I know, I actually studied Greek. Had to look it up and seems Americans, or maybe all English speakers tend to mispronounce it as /mju:/ instead of /my:/ which makes it sound more like mew, which apparently is an alternate term for meow and not just a Pokémon? Funny that I didn't even notice that when Dianna did it.
@@Tharkon Okay, just learned something new myself. Honestly, I'm amazed you researched it. I would add that kittens are more associated with 'mew' as opposed to 'meow', but it's understandable not knowing all cultures' cat onomatopoeia.
Great show
Presidio park!! I love that place!! Luv you and ur channel!! 👍😎
Interesting example of a car, the coefficient of certain materials can change under load, rubber - of which the tires are made - for example. So when the car brakes hard, the energy is shifted to the front tires, increasing the load and thus the Coefficient.
So the actual area of contact on the road is irrelevant - if I remember correctly (probably don't as it's been many years)
"Because the surfaces are rough..."
Or, Ruff, considering Mac the dog was just on screen.
LOL 🤣 😅 🤣
I love the cow you always use in the videos!
Great lesson and that jump suit is so cute!
im horrible with math but i understand physics with visuals. im a mechanic and everything is physics it's pretty cool watching diana do this i find it amazing how things work . when i was young i always wondered why a car can drive better on a paved road then a metal tracked tank logically you would think the tank would to better but it will slide around like being on ice pretty crazy 😜
Cafeteria trays, best sled... er, physics experiment apparatus out there. Great lesson Diana!
Found your channel from a shoutout by BrainCraft. Subbed! 👍
Good marker catch! 😲👍
you're about to save my AP Physics 1 grade, tysm!
Thank you so much.
thank you so much for this❤️
Great full ideas
Just solved my doubts in a fun way 💗🌸
You are always the best
Good book by the way. I have that in my Audible collection.
There are two kinds of friction: the electromagnetic "stickiness", and just the shape alone. In a universe without electromagnetic "stickiness", they would still have friction in our size range. Friction would be a lot less common, and would depend heavily on how smooth a surface is, and what it's made from. They would have a large capacity to select how much friction they want; we are the ones who are mostly forced to deal with having lots of it.
Ice blocking is an awesome activity!
Also, I need a physics girl trademarked square cow merch so I can follow along accurately.
Please and thank you
I enjoyed the Diana's physics.
Really It is awesome.
General Knowledge With SIDRAK try doing some real physics (calculus based physics) then tell me how much you love physics
@@CloroxBleach-hi6jd you know what I do love physics because of some hard concepts and I does learn calculus through physics.
@@awc9811 learning the concepts is fun and easy. Replicating the calculations for the concepts is something else entirely.
@@CloroxBleach-hi6jd you know what I have gained a course through The calculus.
And I've been in calculus almost 10 years OK.
am kidding, but you know you are right
You teach physics better than my university. Loved your video
Minute 7:23. The normal force is not the reaction force to gravity due to Newton's 3rd law. The normal force is eqaul in magnitude and opposite in direction because of Newtons first law.
Are you always this crazy? I love your craziness and keep Physicsing.
I love your channel! :D
Hi Diana, awesome video, I always had doubts on the actual mechanism of friction...
However when you mentioned that molecules bond and break... between surfaces..
Should the chemistry of the surface materials also have some influence on the coefficient of friction? For example if the material sitting on a wooden floor doesn't bond as much with the wood then it's coefficient of friction would be lesser then tan theta right?
Another fab video. Wonder if ice blocking is ever tried with a few blocks and a platform stuck to them to make a sled / sledge
Q: What's the coefficient of friction for a cow on the cover of a physics book?
A: Moo
Very nice video
Never good at math but I love physics,therefore I love your mini lessons.
Nice video. However, there is a misconception at 10:18. Static friction (non slip friction) is NOT equal to mu_s F_N. That value is the maximum non slip friction can be before it starts to slide. The value of the non slip friction is deduced from Newton 2nd law. In the example of the book that does not fall off the wall, the static friction is opposite to the book weight mg, no matter what the value of F_N is. If you don't push hard enough such that mu_s F_N falls below mg then the book will slide.
As a motorcycle fanatic. The most important formula is "Friction + Weight = Grip". This is The lifesever to understand the basics of.
Oooooh, I think a teensy edit at "lifesever" would make the sentence less gruesome.
Love your videos, but one suggestion... include significant digits? Students always struggle with sig digs.
Waiting for next..
Big fan of urs👍👍👍👍
You should have added that friction is not dependent on the surface areas of either of the two objects. It seems counterintuitive - for example the huge tires used on funny cars and dragsters - but that's more for heat dissipation.
Interaction is a reaction and reaction is a reason as knowledge or as acplanation
Thanks for my revision👍🏻
Love from India❤️
It should be emphasized that the tanθ is the coefficient of static (maximum) friction, which is different from the coefficient of kinetic friction.
Thanks 👍
I hated physics all my life. U piqued my intrest in the field. Tks a lot Diana. Love from India.
Time and space are functions of ones conceptual scheme
Diana, you are amazing. I am so glad that you are offering these videos. I had to learn my physics from a book. MIT tried to get me to learn from the Finman lectures, but I have found that Isaac Asimov's "Understanding Physics" (available from Bares and Nobles for $10) is much more accessible. My son and daughter got through college physics with it and I recommend it, to. Though now I have videos to recommend, YOURS! thank you very much.
Another interesting thing to note is that area isn't in the equation either. Of course we know it makes a difference but the simple friction equation would give a good enough estimate for most cases.
Taking friction as chemical molecular forces, could I measure a 'frictional' force between water and dirt at the soap interface? If I can push the analogy that far, would it then be a 'related frictions' problem (in the sense of related rates from calculus)?
You're pretty freakin' awesome!
So does the size of the contact patch area of the two surfaces not matter? Like if I have wide tires compared to regular tires, will I not stop faster?
Ohh my home region has the perfect hill near the place measuring gravitational waves even for this such thing at a school I've done this at many times in my past.
Girl, Thumbs up 👍🏾 Long time♥️🇳🇬