• Support PF! Buy your school textbooks, materials and every day products Here!

Efficiency of a Spring

  • #1

Homework Statement


So, I have a 5.0 kg rat that goes down a ski slope, slides along a rough patch, and then smashes into a vertical board with a spring attached. I need to find out the efficiency of the spring with this information:
m=5.0 kg
v (after sliding across rough patch)=108 m/s ; it also says that because of internal friction, the velocity is 50% than above, so it's 54 m/s (after hitting the board and spring)
[tex]\Delta[/tex]x=2.42 m (the magnitude of the spring's compression)


Homework Equations


e=eout/ein(100%)
Possibly Ek=.5mv2 and Eelastic=.5k([tex]\Delta[/tex]x)2


The Attempt at a Solution


Well, I think that Ein is equal to Ek, as this is the energy required for the spring to compress, but I'm not completely sure of Eout. Is it possibly Eelastic (I know this value from a previous question)? If I use these two though, I get an answer around 400%, which is obviously wrong.
 

Answers and Replies

  • #2
PhanthomJay
Science Advisor
Homework Helper
Gold Member
7,135
475
Are you saying that it hits the spring with a velocity of 104m/s, then exits the spring with a velocity of 54m/s? It might be best to state the problem as exactly worded (both parts).
 

Related Threads for: Efficiency of a Spring

  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
3
Views
892
  • Last Post
Replies
5
Views
590
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
3
Views
4K
  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
7
Views
1K
  • Last Post
Replies
2
Views
764
Top