Homework Help: 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?