# Spring Compression

1. Feb 24, 2010

### contlee

A 2kg block is placed pushing against a spring. The spring is compressed and stores 10 joules of potential energy. The block remains attached to the spring as it oscillates on a frictionless track.

The mass experiences zero acceleration when the spring compression is __________
A. greatest
B. When velocity is zero
C. At the equilibrium
D. Kinetic Energy is zero
E. Potential energy is greatest

I have no idea. I think the answer is A. But however I have no concrete reason why. So far I am basing my answer on the fact that when the compression is greatest the block is not moving. Therefore the acceleration is zero, but then again choice B says when the velocity is zero. Any ideas

2. Feb 24, 2010

### rl.bhat

In the spring the relation between force and compression is given by
F = -k*x, where k is the spring constant. The acceleration is zero when F is zero.
Now where the force is zero?

3. Feb 24, 2010

### contlee

I'm still confused so the acceleration is o when the compression is kinetic energy is zero

4. Feb 24, 2010

### rl.bhat

No. In fact when the acceleration is zero, kinetic energy is maximum. In the oscillating body where the kinetic energy is maximum?