@@AllenTsaoSTEMCoach i wanted to see the questions, but they were not published, my son told me that there was an elevator problem and it was really funny because i did teach him the elevator workings. I stand him up and pull his hair up, and also i would put weight on his shoulders, basically trying to simulate the change in normal force, but making sure he understood that force of gravity was constant. Aparently he got it. I tried to be creative on my teachings, i am not a teacher.
There is a simpler way of doing part a). From the components, calculate the time of flight using a = delta v_y/t. Times by 2 as same up and down. Then use x = v_x t and simplify.
That's a great point! I tend to not use too many shortcuts when teaching because that's only applicable when the launch and landing is at the same height. But it is a very useful trick.
Thanks for the great video but some points. In part a, the answer could have been driven easier like when you apply the conservation of energy and easily figure out the cyclist velocity at the end of the ramp and decompose it into x and y directions. Using the equation y=V0y*t+1/2gt^2 the amount of time would be t= 2*sqrt(2gH)*sin(θ)/g and then simply plug it in X0= V0x*t and X0=4*H0*cos(θ)*sin(θ). The last part of the question is asking about the vertical components of velocity so I think you should have put sqrt(2gH0)*sin (θ) instead of sqrt(2gH0).
Nice video, Coach. I wanted to add that the time in Part a and the graph in Part c can both be found by using v = v0 + at with v0 = sqrt(2gH0)*sin(theta) and a = -g. For Part a, the final vertical velocity is opposite the initial vertical velocity, so v = -v0. For Part c, this would give you a linear equation in t with a negative slope of -g. You did mention that you rather avoid special cases and another person mentioned this in their comment below.
Really think your runthrough of the exam was great. Saw Q#5 AP Physics 1 and Commented on that too. the end of course Questions help teach me in a clear but detailed way much like Precalculus Reviews from Organic Chem Tutor. You influence growing college and high schoolers to see the many project-styled lessons in Physics and rationalize the standards and objectives in algebraic and common sense ways. And this is Year 1 University science major Physics -- that's pretty tough! Thank you. ♥♥😃
Thanks. It's been already noted and the description does have the correction. Unfortunately TH-cam doesn't allow you to edit a video after it's uploaded.
What program are you using to work out the questions? I love that you can scroll and the writing is still there. Thanks in advance for your response. Would love to use this in my classroom, thanks.
I don't understand why the PE at the top of the ramp is equal to the KE at the launch point. I thought that the ME at the launch point would be a mixture of KE and PE because it is above the ground.
It depends on how you set your reference height. I put the reference height of h=0 at the point of launch. You can height h=0 to be the ground but then the initial PE is at a height H+height of ramp. You would still get the same answer
For part b) If twice the height produces twice the velocity, then it would clear twice the cars. But although height is directly proportional to energy, energy is not directly proportional to velocity. If the velocity doubles, it will travel twice as far, but since velocity is proportional to the sqrt of the height, shouldn't twice the height produce less than twice the velocity, and therefore less than twice the amount of cars?
Twice the velocity does not give twice the distance. It gives 4x the distance. The time in the air is increased *and* the horizontal velocity is doubled. Thus, twice the velocity results in 4x the distance traveled.
@@AllenTsaoSTEMCoach I was only thinking twice the horizontal velocity, but yes, now that makes sense since its also doubles the time in the air, twice the time and twice the horizontal velocity gives four times the distance.
If I messed up finding t but did everything else right and got h*sin(theta)*cos(theta) and I got the same things as you for the other part how many points would I get? For the c question I got your answer * sin(theta)
I'm not a reader, so I'm not super well versed in the scoring mechanics. I'd say that would dock you 1 point (2 points at most), so I'd say you would receive 5 or 6 points for it.
You are allowed to use that variable but you are not required to. The answer would actually not depend on the mass. Your kinematic equations are not affected by mass, for example.
so if the questions from admin 2 will be different from admin 1 are they going to be similar type question approach or will students be wasting their time using your videos as a study guide if they are taking the test admin2? Although I think the videos are excellent I would not want to spend time reviewing them when I could be doing something from elsewhere.
So they will be a completely different set of FRQs. I treat these as the same as the previous year FRQs (2015 to 2019 ones excluding waves, circuits, and electrostatics). They're good to practice to hone your skill at problem solving, but I would not rely on them to try to "guess" what's on the test. The videos are originally meant for students who took the admin 1 who were curious about the answers (I'll do the same for the admin 2 questions when they're released). For students currently prepping for admin 2, I would suggest they *try* the problems themselves without seeing any solutions to assess what they can do and what they can't do, and viewing the solutions to help them see what they may have missed.
@@AllenTsaoSTEMCoach so if some students took admin 1 and the others will take admin 2 they will be taking a completely different test? or...will the question be the same category but just different. As in QQT, Scientific method analysis...etc
Mr Bothell, when it tell you to derive an equation in terms of x,y,z.. do you need to have all of those variables in your final answer to get full credit?
Some variables they give you might be terms that ultimately cancel out, like mass in this example. I've also seen examples where they give you red-herring variables for that list, that you wouldn't even introduce to your work in the first place. An example of a red herring variable for this problem, would be R, for the launch ramp's radius of curvature. You just couldn't use a problem-specific variable they don't give you in the list, like v0 in this case for the speed at launch. "Physical constants" would include terms like Earth's g, pi, the universal big G, the Coulomb constant, and similar numbers that rarely (if ever) would be different from the standard number you use most of the time.
Thanks for making this video, however, there are some errors with the work that you did. Most notably in your graph of the cyclist's vertical component of the velocity you put the cyclists speed as the labels, when it asked for the vertical component of the velocity. Should be sqrt(2gh)(sin(theta)). You are also able to simplify the equation you use in the horizontal distance to be 2Hsin(2theta), using the trig identity 2sin(theta)cos(theta)= sin(2theta).
The graph error was caught and noted. Also part a) should be a 4, not a 2. However, you are not required to use a trig identity to simplify although I make it clear that you may simplify it that way if you want.
@@AllenTsaoSTEMCoach Yeah sorry I watched this without the audio because I am in class right now. You are correct in saying that the coefficient is 4 not two. However when you simplify 4Hsin(theta)cos(theta), it becomes 2Hsin(2theta), where the coefficient is 2 not 4. The trig identity is: 2sin(theta)cos(theta)= sin(2theta).
Yep it should be 4. I think I mixed up in my head because I was thinking of making it sin(2theta) and dropping the 2, but I didn't do that. Good catch!
sorry just saw someone already commented on this. saw the 4 reply in part a. simple mistakes. hopefully this is scored based on process and not correct answers
It's okay if you didn't do well. Lots of things can happen during a test. But keep in mind that 50% points is a passing score and multiple choice is worth half of the score too.
@@AllenTsaoSTEMCoach I definetely got this question wrong because I failed to derive the time, but I got the v component correctly. Do you think I'll get partial credit for that? I did well on the other FRQs. Thank you for posting these!
Well I don't think the questions are easier in AP Physics C. But it's scored a lot easier. A 55% -60% on Physics C can get you a 5 whereas you need more like 70% in Physics 1. Also, the physics C test is a little shorter so maybe you aren't nearly as tired by the time you get to the FRQs.
This is the WORST FRQ I have ever seen. Once the initial equations is completed, This becomes an algebra problem. Man, I thought they were getting away from this kind of stuff. Seriously, what is going on here?
I'm not sure. It's intended as a college level physics class, and this level of algebra is not that unusual for a college level physics class. I'd agree that it might have been more elaborate than in past years. I suspect the dropping of 3 units meant they were going to make the test more rigorous on the remaining topics. It was a tough question for a lot of students for sure.
bruh this question was the finisher in my hopes for passing this exam. Had absolutely no idea what I was doing, and spent almost all my time on it
I skipped it and did it last. Glad i did since im pretty sure i did it right
this was easier than 4 and 5
I think since it wants the verticle component for velocity in part c it is the v0 * sin(theta)
Yep, I was just about to comment
Agreed!
The equation should have a 4 not a two. Even if you look at your work, you just made a small mistake. Great videos!
Yeah that threw me off
@@fancywhale1881 I thought I was crazy for a minute.
My son got a 3 and I cried tears of Joy, we studied together and it was really hard.
That's amazing and I'm so happy for the both of you. I heard the second administration was pretty difficult.
@@AllenTsaoSTEMCoach i wanted to see the questions, but they were not published, my son told me that there was an elevator problem and it was really funny because i did teach him the elevator workings. I stand him up and pull his hair up, and also i would put weight on his shoulders, basically trying to simulate the change in normal force, but making sure he understood that force of gravity was constant. Aparently he got it. I tried to be creative on my teachings, i am not a teacher.
That's really cool that you used such creatine ways to teach that!
There is a simpler way of doing part a). From the components, calculate the time of flight using a = delta v_y/t. Times by 2 as same up and down. Then use x = v_x t and simplify.
That's a great point! I tend to not use too many shortcuts when teaching because that's only applicable when the launch and landing is at the same height. But it is a very useful trick.
Thanks for the great video but some points. In part a, the answer could have been driven easier like when you apply the conservation of energy and easily figure out the cyclist velocity at the end of the ramp and decompose it into x and y directions. Using the equation y=V0y*t+1/2gt^2 the amount of time would be t= 2*sqrt(2gH)*sin(θ)/g and then simply plug it in X0= V0x*t and X0=4*H0*cos(θ)*sin(θ). The last part of the question is asking about the vertical components of velocity so I think you should have put sqrt(2gH0)*sin (θ) instead of sqrt(2gH0).
Nice video, Coach. I wanted to add that the time in Part a and the graph in Part c can both be found by using v = v0 + at with v0 = sqrt(2gH0)*sin(theta) and a = -g. For Part a, the final vertical velocity is opposite the initial vertical velocity, so v = -v0. For Part c, this would give you a linear equation in t with a negative slope of -g. You did mention that you rather avoid special cases and another person mentioned this in their comment below.
Yea this is what I did. Glad to know it works
Really think your runthrough of the exam was great. Saw Q#5 AP Physics 1 and Commented on that too. the end of course Questions help teach me in a clear but detailed way much like Precalculus Reviews from Organic Chem Tutor. You influence growing college and high schoolers to see the many project-styled lessons in Physics and rationalize the standards and objectives in algebraic and common sense ways. And this is Year 1 University science major Physics -- that's pretty tough! Thank you. ♥♥😃
ERROR at 6:53 its Xo= 4 Ho Sin Thetha Cos Theta not "2"
Thanks. It's been already noted and the description does have the correction. Unfortunately TH-cam doesn't allow you to edit a video after it's uploaded.
What program are you using to work out the questions? I love that you can scroll and the writing is still there. Thanks in advance for your response. Would love to use this in my classroom, thanks.
I use OneNote, the windows store app version. You can drag PDF files in (insert as printout) and it'll load each page of the PDF like that.
@@AllenTsaoSTEMCoach Thank you.
I don't understand why the PE at the top of the ramp is equal to the KE at the launch point. I thought that the ME at the launch point would be a mixture of KE and PE because it is above the ground.
It depends on how you set your reference height. I put the reference height of h=0 at the point of launch.
You can height h=0 to be the ground but then the initial PE is at a height H+height of ramp. You would still get the same answer
@@AllenTsaoSTEMCoach i see. thank you.
For part b) If twice the height produces twice the velocity, then it would clear twice the cars. But although height is directly proportional to energy, energy is not directly proportional to velocity. If the velocity doubles, it will travel twice as far, but since velocity is proportional to the sqrt of the height, shouldn't twice the height produce less than twice the velocity, and therefore less than twice the amount of cars?
Twice the velocity does not give twice the distance. It gives 4x the distance. The time in the air is increased *and* the horizontal velocity is doubled. Thus, twice the velocity results in 4x the distance traveled.
@@AllenTsaoSTEMCoach I was only thinking twice the horizontal velocity, but yes, now that makes sense since its also doubles the time in the air, twice the time and twice the horizontal velocity gives four times the distance.
@@AllenTsaoSTEMCoach and of course sqrt of 4 is 2 so therefore twice the distance in this case!
Wouldn’t the graph be root2gh0 x sin theta
Yep it is the vertical component. You're right.
Yep that's what I also thought
why didn't you multiply by the square root of the velocity when you did the Vo * t in part a?
Well there's a vo in t so I knew it would become vo^2.
Dang it I got 4 instead of 2 for the coefficient in the first problem how many points off is that
4 is correct. I had it wrong.
@@AllenTsaoSTEMCoach alright, thanks
Yeah I did too and I was confused until I saw this, glad to see it was 4 😅
If I messed up finding t but did everything else right and got h*sin(theta)*cos(theta) and I got the same things as you for the other part how many points would I get? For the c question I got your answer * sin(theta)
I'm not a reader, so I'm not super well versed in the scoring mechanics. I'd say that would dock you 1 point (2 points at most), so I'd say you would receive 5 or 6 points for it.
don't you need mass in the final equation, I was taught that it has to be in there because it says "in terms of m"
You are allowed to use that variable but you are not required to. The answer would actually not depend on the mass. Your kinematic equations are not affected by mass, for example.
so if the questions from admin 2 will be different from admin 1 are they going to be similar type question approach or will students be wasting their time using your videos as a study guide if they are taking the test admin2? Although I think the videos are excellent I would not want to spend time reviewing them when I could be doing something from elsewhere.
So they will be a completely different set of FRQs. I treat these as the same as the previous year FRQs (2015 to 2019 ones excluding waves, circuits, and electrostatics). They're good to practice to hone your skill at problem solving, but I would not rely on them to try to "guess" what's on the test.
The videos are originally meant for students who took the admin 1 who were curious about the answers (I'll do the same for the admin 2 questions when they're released). For students currently prepping for admin 2, I would suggest they *try* the problems themselves without seeing any solutions to assess what they can do and what they can't do, and viewing the solutions to help them see what they may have missed.
@@AllenTsaoSTEMCoach so if some students took admin 1 and the others will take admin 2 they will be taking a completely different test? or...will the question be the same category but just different. As in QQT, Scientific method analysis...etc
They'll be the same question types for the standard paper exam. QQT, Paragraph answer, experimental design, and 2 short answer.
Where can I find the 2021 unanswered released questions?
On AP Central:
apcentral.collegeboard.org/courses/ap-physics-1/exam?course=ap-physics-1-algebra-based
Mr Bothell, when it tell you to derive an equation in terms of x,y,z.. do you need to have all of those variables in your final answer to get full credit?
No you do not have to use all the variables. You just can't use any other variables.
Some variables they give you might be terms that ultimately cancel out, like mass in this example. I've also seen examples where they give you red-herring variables for that list, that you wouldn't even introduce to your work in the first place. An example of a red herring variable for this problem, would be R, for the launch ramp's radius of curvature.
You just couldn't use a problem-specific variable they don't give you in the list, like v0 in this case for the speed at launch. "Physical constants" would include terms like Earth's g, pi, the universal big G, the Coulomb constant, and similar numbers that rarely (if ever) would be different from the standard number you use most of the time.
Will you be going over AP Chemistry?
Sorry I'm not that great at chemistry
Thanks bro!
who else regrets not taking 3rd admin after seeing this
Thanks for making this video, however, there are some errors with the work that you did. Most notably in your graph of the cyclist's vertical component of the velocity you put the cyclists speed as the labels, when it asked for the vertical component of the velocity. Should be sqrt(2gh)(sin(theta)). You are also able to simplify the equation you use in the horizontal distance to be 2Hsin(2theta), using the trig identity 2sin(theta)cos(theta)= sin(2theta).
The graph error was caught and noted. Also part a) should be a 4, not a 2. However, you are not required to use a trig identity to simplify although I make it clear that you may simplify it that way if you want.
@@AllenTsaoSTEMCoach Yeah sorry I watched this without the audio because I am in class right now. You are correct in saying that the coefficient is 4 not two. However when you simplify 4Hsin(theta)cos(theta), it becomes 2Hsin(2theta), where the coefficient is 2 not 4. The trig identity is: 2sin(theta)cos(theta)= sin(2theta).
Do they ever release the MC section and the answers?
They don't unfortunately.
Thanks for the excellent video.
in your last step on part a the coefficient should be 4 not 2
nah its 2
Mb ur right
Yep it should be 4. I think I mixed up in my head because I was thinking of making it sin(2theta) and dropping the 2, but I didn't do that. Good catch!
@@AllenTsaoSTEMCoach we all do it from time to time. I tell my students, "I Physics great, math Ok, and English horribly."
@@ryanmcdowell246haha I love that line.
basically impossible. I just put f=ma or something and did the other questions and somehow i got a 3 on the exam lol
I said 12 cars but pulled it out of my ass. Do I get any points for that?
It would depend what you wrote. But they usually want to see a reasonable justification with your answer.
this question is rough. your answer to part c needs to be multiplied by sin theta
sorry just saw someone already commented on this. saw the 4 reply in part a. simple mistakes. hopefully this is scored based on process and not correct answers
i failed
It's okay if you didn't do well. Lots of things can happen during a test. But keep in mind that 50% points is a passing score and multiple choice is worth half of the score too.
@@AllenTsaoSTEMCoach I definetely got this question wrong because I failed to derive the time, but I got the v component correctly. Do you think I'll get partial credit for that? I did well on the other FRQs. Thank you for posting these!
You're very welcome. The derivation is worth a lot of points probably so I think you will get some credit depending on what you showed.
Cocomelon Army enjoyed this problem
Hello from Cacara discord
This is why I decided to take ap physics c over this, in my school it’s considered much easier
Well I don't think the questions are easier in AP Physics C. But it's scored a lot easier. A 55% -60% on Physics C can get you a 5 whereas you need more like 70% in Physics 1. Also, the physics C test is a little shorter so maybe you aren't nearly as tired by the time you get to the FRQs.
im cooked
Lmaoooo, this ques is pretty tricky too so dw
does your wife like physics
Kind of a strange question, but yes she does! We met in physics class in college actually.
This is the WORST FRQ I have ever seen. Once the initial equations is completed, This becomes an algebra problem. Man, I thought they were getting away from this kind of stuff. Seriously, what is going on here?
I'm not sure. It's intended as a college level physics class, and this level of algebra is not that unusual for a college level physics class. I'd agree that it might have been more elaborate than in past years. I suspect the dropping of 3 units meant they were going to make the test more rigorous on the remaining topics. It was a tough question for a lot of students for sure.