# Homework Help: Mass collides with spring and mass

1. Jun 25, 2012

### NRasmus1

A block of mass m1=1.60kg initially moving to the right with a speed of +4.00m/s on a frictionless horizontal track collides with a spring attached to a second block of mass m2=2.10kg initially moving to the left with a speed of -2.50m/s. The spring constant is 600N/m. At the instant block 1 is moving to the right with a speed of +3.00m/s, determine the velocity of block 2. Determine the distance the spring is compressed at that instant.

KE=1/2mv^2
Elastic PE=1/2Kx^2
Fp=Kx
Fs=-Kx

I'm going to start with conservation of energy, but this is too complex of a system for me to even begin. A step by step of how to set up this equation would be most helpful. Thank you all for your help!
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Jun 25, 2012

### Xisune

Try conservation of momentum.

3. Jun 25, 2012

### azizlwl

Use both conservation of energy and comservation of momentum to get 2 equations for the 2 unknowns.