[SOLVED] Conservation of Energy Problem - Need Help 1. The problem statement, all variables and given/known data A 2.0 kg cart has a sping with k= 5000 N/m attached to its front, parallel to the ground. This cart rolls at 4.0 m/s toward a stationary 1.0 kg cart. a) What is the maximum compression of the spring during the collision? b) What is the speed of each cart after the collision? 2. Relevant equations KE=(1/2)mv^2 Us=(1/2)kx^2 3. Attempt at a solution I got the first part: Using first conservation of momentum and assuming the cars stick together momentarily then using conservation of energy (2kg)(4m/s)=(3kg)v1 v1= 2.67 m/s (.5)(2kg)(4m/s)^2=(.5)(5000N/m)(x)^2 + (.5)(3kg)(2.67m/s)^2 x= .046 m But I'm not sure what to do with the second part. Any suggestions?