Homework Help: Physics Help

1. Feb 22, 2005

Okay...so I have Physics homework due at midnight, 8 hours. And I'm stuck on a few problems...posting here for some help.
An explanation of how to do it would be much more appreciated then just answer.

1a)A 1816 g mass is on a horizontal surface with μk = 0.48, and is in contact with a massless spring with a force constant of 610 N/m which is compressed. When the spring is released, it does 1.952 J of work on the mass while returning to its equilibrium position. Calculate the distance the spring was compressed. Figured this out to be just 1.952 = .5kx^2. Before I was factoring in friction.
b)What is the velocity of the mass as it loses contact with the spring?

2a)A 0.65 kg mass sliding on a horizontal frictionless surface is attached to one end of a horizontal spring (with k = 850 N/m) whose other end is fixed. The mass has a kinetic energy of 17.0 J as it passes through its equilibrium position (the point at which the spring force is zero). At what rate is the spring doing work on the mass as the mass passes through its equilibrium position?
b)At what rate is the spring doing work on the mass when the spring is compressed 0.100 m and the mass is moving away from the equilibrium position?

I'm lost with springs.

Thanks...

Last edited: Feb 22, 2005