Physics
posted by John .
In Figure 961, block 1 (mass 2.0 kg) is moving rightward at 8 m/s and block 2 (mass 4.8 kg) is moving rightward at 2.8 m/s. The surface is frictionless, and a spring with spring constant of 1180 N/m is fixed to block 2. When the blocks collide, the compression of the spring is maximum at the instant the blocks have the same velocity. Find the maximum compression.

Using conservation of momentum:
2*8 + 4.8*2.8 = (2+4.8)*vf = 6.8*vf
Solve for vf, the final speed of the blocks when they have the same velocity.
1/2*k*x^2 = 1/2*m*vf^2
Solve for x; k is the spring constant = 1180 N/m; x is the maximum compression of the spring