# Spring help

1. Nov 23, 2003

### physics333

A block having a mass of 2.80 kg is given an initial velocity of 1.2m/s when it collides with a spring. The constant force of friction acts between the block and the surface with (mu sub k=0.5) and the force constant of the spring is k=100N/m. What is the maximum compression?

I've been stuck on the problem for a while.
Workfriction + KEi + PEi = KE + PE

KEi =2.02J
fk =13.72
KE=0
PEi =0

therefore (13.72 N + 2.02 J)/ 50N/m = x^2

Is this equation right? If so, how do I find x?
I tried to work it but I can't figure out how to add newtons and joules divided by N/m and end up with x in meters...

Last edited: Nov 23, 2003
2. Nov 23, 2003

### StephenPrivitera

1N=1kgm/s2 ---- remember F=ma?
1J=1kgm2/s2 ----- remember W=Fx?

3. Nov 23, 2003

### physics333

I still need more information....I'm not as smart as some as you. Someone get me started and I can figure it out...
Thanks

4. Nov 24, 2003

### NateTG

There should be massive alarms going off when you get N+J in a physics problems.

If you put your equation together right, this should be easy:

KEi=Workfriction+PEspring
or
1/2mv02=ffrictionx+1/2kx2