Potential-energy diagram help

  • Thread starter fsm
  • Start date
  • #1
fsm
88
0
I am given a potential-energy diagram with the vertical axis is potential-energy and the horizontal axis is x. The mass of the particle is 500g.
knight_Figure_10_30.jpg


They are asking the velocities of b, c, and d. I am completely lost. I can't even find an example in the book. This isn't good :(
 

Answers and Replies

  • #2
berkeman
Mentor
60,583
10,899
The Homework Posting Template asks you to list what equations and principles apply to your problem. What can you say about changes in PE? What is the PE of a mass that is raised some height against the force of gravity?
 
  • #3
312
0
If its not potential then what is it?
 
  • #4
berkeman
Mentor
60,583
10,899
If what's not potential?

There are several different sources of PE, right? It can come from compression of a spring, or storing compressed air, or the form that I think the OP problem is referring to. But without the exact problem statement and context, it's hard to say.

fsm -- can you please post the exact text of the question, and maybe say what you are studying at the moment. And then offer some ideas about how to solve the problem.
 
  • #5
20
0
Hi fsm,

U need to know how to interpret graphs and the conservation of mechanical energy to do this. Ok, initially, the total energy of the particle is 5J. At point B, it has lost some P.E. and what's left is 2J. Some of the P.E. has been converted into K.E. which is 3J. U know the mass of the particle (500g). U can use the equation K.E. = 1/2 mv² and solve for v. Do the same for points C and D. U should get the answers pretty fast.

Hope that helps.
 
  • #6
berkeman
Mentor
60,583
10,899
Hi fsm,

U need to know how to interpret graphs and the conservation of mechanical energy to do this. Ok, initially, the total energy of the particle is 5J. At point B, it has lost some P.E. and what's left is 2J. Some of the P.E. has been converted into K.E. which is 3J. U know the mass of the particle (500g). U can use the equation K.E. = 1/2 mv² and solve for v. Do the same for points C and D. U should get the answers pretty fast.

Hope that helps.

Except, what if it's a ball rolling down an incline without slipping -- how does that change the velocity answer? And what would be different if it were a cylinder instead of a ball? We aren't given enough information by the OP to just say use 1/2mv^2.
 

Related Threads on Potential-energy diagram help

Replies
13
Views
158
  • Last Post
Replies
12
Views
1K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
0
Views
2K
  • Last Post
Replies
8
Views
2K
  • Last Post
Replies
16
Views
7K
  • Last Post
Replies
8
Views
1K
  • Last Post
Replies
14
Views
8K
  • Last Post
Replies
5
Views
3K
  • Last Post
Replies
17
Views
2K
Top