Spring constant and energy

  • #1

Homework Statement



1.JPG

Homework Equations




The Attempt at a Solution



EPE is (0.5)kx^2

Let Y have spring constant of K then X has spring constant of 2K

So EPE of Y is (0.50kx^2 which is E

So EPE of X must be (0.5)2kx^2 which is kx^2 which is 2E? But correct answer is E/2??
 

Answers and Replies

  • #2
gneill
Mentor
20,925
2,867
It looks like you've assumed that x is the same for both springs. Is that going to be the case?
 
  • #3
It looks like you've assumed that x is the same for both springs. Is that going to be the case?

Ah, in that case if X has a stiffer spring, 2K, then its extension (x) will only be half, so we'd have (0.5)(2K)(0.5x) so the energy stored is the same for both??
 
  • #4
gneill
Mentor
20,925
2,867
Ah, in that case if X has a stiffer spring, 2K, then its extension (x) will only be half, so we'd have (0.5)(2K)(0.5x) so the energy stored is the same for both??
Check the expression you've just used for the energy. Did you forget something?
 
  • Like
Likes ravsterphysics
  • #5
Check the expression you've just used for the energy. Did you forget something?

Argh such a silly mistake! Thanks for your help : )
 

Related Threads on Spring constant and energy

  • Last Post
Replies
8
Views
2K
Replies
6
Views
4K
Replies
1
Views
2K
Replies
3
Views
3K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
4
Views
19K
  • Last Post
Replies
1
Views
2K
Replies
1
Views
5K
Replies
6
Views
4K
Top