Understanding the Solution to an AP Physics C Exam Problem

  • Thread starter keydetpiper
  • Start date
  • Tags
    Ap Exam
In summary, the conversation discusses a problem from the 1982 AP Physics C exam, specifically part c of the problem which involves a block on a slope and a compressed spring. The question is how the maximum speed occurs as the spring is being compressed. The solution explains that the block is still subject to its weight and will continue to accelerate until the force from the spring cancels it out. This force is dependent on how much the spring is compressed. The person asking the question initially thought the block would start slowing down when the spring exerts a force on it, but understands now that it will continue to accelerate until the force from the spring balances it out.
  • #1
keydetpiper
3
0
[SOLVED] Help on an AP exam problem

I teach AP physics in high school and encountered this problem, from the 1982 AP Physics C exam. http://keydetpiper.com/Misc/1982C.html" has a link to the original problem (#2) and the official solution.

My question is regarding part c: how is it possible that the maximum speed happens as the spring is compressed? Seems to me that as soon as the spring is compressed it exerts a force on the block, and since that force will be in the opposite direction of the velocity it will create a negative acceleration. Am I missing something?
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
As the solution states the block will still be subject to its weight acting along the slope and will thus still be accelerating until the force from the spring exactly cancels it. The force from the spring is dependent on how much the spring is compressed (i.e. [itex] F = -kx [/itex] if it obeys Hooke's law).
 
  • #3
Yeah, ok thanks. Don't know why I couldn't see it before... I was thinking it would start to slow down as soon as the spring starts putting a force on it. I get it now, thanks for your response!
 

What is the best way to approach an AP exam problem?

The best way to approach an AP exam problem is to read the question carefully and identify what it is asking for. Then, create a plan or outline for solving the problem, and check your work for accuracy and completeness before submitting your answer.

How should I manage my time when working on an AP exam problem?

It is important to pace yourself and allocate enough time for each problem on the AP exam. If you are struggling with a particular problem, it may be beneficial to move on to another one and come back to it later. Keep an eye on the time and make sure you are not spending too much time on one problem.

Should I show all of my work on an AP exam problem?

Yes, it is important to show all of your work on an AP exam problem. This not only helps you to organize your thoughts and calculations, but it also allows the grader to see your reasoning and give partial credit if your final answer is incorrect.

What should I do if I get stuck on an AP exam problem?

If you get stuck on an AP exam problem, try taking a step back and approaching it from a different angle. You can also try breaking the problem down into smaller parts or seeking help from your teacher or classmates. Remember to manage your time and not spend too much time on one problem.

How can I prepare for AP exam problems?

The best way to prepare for AP exam problems is to practice consistently throughout the year. This includes completing practice problems, reviewing class notes and materials, and seeking help from your teacher when needed. It is also important to familiarize yourself with the AP exam format and question types.

Similar threads

Understanding the Forces Behind Part B of the Graph
    • Introductory Physics Homework Help
Replies
10
Views
1K
A block of mass m is dropped onto the top of a vertical spring....
    • Introductory Physics Homework Help
Replies
8
Views
4K
Mech#3 on 1974 AP "C" Exam -- 2 Blocks Connected by a Spring
    • Introductory Physics Homework Help
Replies
3
Views
1K
AP Physics C E&M: Struggling with Homework Before Exam
    • Introductory Physics Homework Help
Replies
6
Views
2K
AP Physics Exams: College Apps & Self-Studying Tips
    • STEM Academic Advising
Replies
2
Views
1K
Where to find AP Physics C: Mechanics material?
    • Introductory Physics Homework Help
Replies
1
Views
2K
AP Physics C Momentum Problem: A dart launched horizonally by a spring gun
    • Introductory Physics Homework Help
Replies
22
Views
4K
A rod at rest on ice is struck by a piece of clay....
    • Introductory Physics Homework Help
Replies
10
Views
2K
Teaching high school AP physics
    • STEM Educators and Teaching
Replies
7
Views
4K
Various Physics Practice Problems for Exam
    • Introductory Physics Homework Help
Replies
1
Views
1K

Hot Threads

Recent Insights

Back
Top