Elastic potential energy

  • Thread starter Smartgurl
  • Start date
  • #1
15
0

Homework Statement


A small truck is equipped with a rear bumper that has a spring constant of 8 x 10^5 N/m. The bumper can be compressed 15 cm without causing damage to the truck. What is the maximum velocity with which a solid 1000kg car can collide with the bumper without causing damage to the truck?[/B]


Homework Equations


Ek = 1/2 mv^2
El = 1/2 kx^2

The Attempt at a Solution


I made these two equations equal to each other and got the answer 4.2 m/s. The right answer is 34 m/s. I'm way off and not sure what I'm doing wrong
 

Answers and Replies

  • #2
20,579
4,425

Homework Statement


A small truck is equipped with a rear bumper that has a spring constant of 8 x 10^5 N/m. The bumper can be compressed 15 cm without causing damage to the truck. What is the maximum velocity with which a solid 1000kg car can collide with the bumper without causing damage to the truck?[/B]


Homework Equations


Ek = 1/2 mv^2
El = 1/2 kx^2

The Attempt at a Solution


I made these two equations equal to each other and got the answer 4.2 m/s. The right answer is 34 m/s. I'm way off and not sure what I'm doing wrong
Does 34 m/s seem like a reasonable speed at which damage would be avoided?

Chet
 
  • #3
15
0
Does 34 m/s seem like a reasonable speed at which damage would be avoided?

Chet
No now that I think about it that's not reasonable. Does that mean I'm actually doing it right?
 
  • #4
20,579
4,425
No now that I think about it that's not reasonable. Does that mean I'm actually doing it right?
4.2 m/s sounds much more like it, doesn't it?

Chet
 
  • #5
15
0
4.2 m/s sounds much more like it, doesn't it?

Chet
Yes it does! I guess it's one of those rare occasions when the textbook is wrong! Thanks! I'll definitely make sure the answer is reasonable next time
 

Related Threads on Elastic potential energy

  • Last Post
Replies
1
Views
583
  • Last Post
Replies
8
Views
957
  • Last Post
Replies
1
Views
730
  • Last Post
Replies
1
Views
747
  • Last Post
Replies
4
Views
360
  • Last Post
Replies
4
Views
1K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
2
Views
6K
Top