# Spring Energy (Finding Velocity)

1. Jun 1, 2013

### Sam Fred

1. The problem statement, all variables and given/known data
A spring AB or constant k = 2N/m is attached to a support A and to a collar of mass
m=1kg. The unstretched length of the spring is 1m, Knowing that the collar is released
from rest at x = x0 = 0.9 m and neglecting friction between the collar and the horizontal
rod, determine the magnitude of the velocity of the collar as it passes through point C.
here l = 1.2m,

2. Relevant equations
T1 + U1-2 = T2
T Kinetic Energy
U Potential Energy

3. The attempt at a solution
I just wanted to see if the answer is right ??

2. Jun 2, 2013

Looks okay.

3. Jun 2, 2013

### TSny

I don't think you handled the work done by the spring correctly. It is not k(.3)2/2.

4. Jun 2, 2013

### lewando

I don't see it... I thought he was correct noting the length of the spring changes from 1.5m to 1.2m.

5. Jun 2, 2013

### TSny

x22-x12 ≠ (x2-x1)2

6. Jun 2, 2013

### lewando

Now I see it...thanks.