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

Finding the distance a spring compresses

  • Thread starter dal11
  • Start date
  • #1
9
0

Homework Statement



An object of mass m=2.2 kg is travelling on a horizontal surface. The coefficient of kinetic friction between the object and the surface is µk=0.2. The object has speed v=0.57 m/s when it reaches x=0 and encounters a spring. The object compresses the spring a distance d/2, stops instantaneously, and then travels back to x=0 where it stops completely. What is the total distance, d, that the object moves after first touching the spring?


Homework Equations



KE+Espring = KEi+Wfriction
Espring=.5k(x^2)
Fspring=kx

The Attempt at a Solution



I am really confused I don't think I have enough knowns to solve the problem.
 

Answers and Replies

  • #2
LowlyPion
Homework Helper
3,090
4

Homework Statement



An object of mass m=2.2 kg is travelling on a horizontal surface. The coefficient of kinetic friction between the object and the surface is µk=0.2. The object has speed v=0.57 m/s when it reaches x=0 and encounters a spring. The object compresses the spring a distance d/2, stops instantaneously, and then travels back to x=0 where it stops completely. What is the total distance, d, that the object moves after first touching the spring?


Homework Equations



KE+Espring = KEi+Wfriction
Espring=.5k(x^2)
Fspring=kx

The Attempt at a Solution



I am really confused I don't think I have enough knowns to solve the problem.
I think you may have more information than you realize.

You start with an initial KE at x = 0.

There are two sources of work against the mass from that point.

There is friction and the spring.

But the spring gains potential energy ... but then gives it back until the object it at rest just as it gets to x = 0 again. So how much net work did the spring do?
 
  • #3
9
0
0 I guess, I don't understand how that helps
 
  • #4
LowlyPion
Homework Helper
3,090
4
0 I guess, I don't understand how that helps
If the spring does no net work in stopping the object doesn't all of the kinetic energy of the object need to be accounted for by just the friction over the distance of 2*(d/2) ?

Doesn't mv2/2 = Work of Friction = Ffriction * distance
 

Related Threads on Finding the distance a spring compresses

Replies
12
Views
2K
Replies
8
Views
14K
Replies
2
Views
5K
Replies
15
Views
3K
  • Last Post
Replies
13
Views
2K
Replies
8
Views
5K
Replies
1
Views
4K
Replies
6
Views
2K
  • Last Post
Replies
3
Views
2K
Replies
5
Views
4K
Top