1. The problem statement, all variables and given/known data A 6kg block slides on a horizontal frictionless surface with a speed of 1.2 m/s. It is brought momentarily to rest when it hits a bumper that compresses a spring. Heres a picture of the problem. When I was doing this problem, I thought there were only two different energies: the Kinetic Energy and the Elastic Potential Energy. I assumed there was no Gravitational PE b/c there was no height involved. Therefore, I assumed (according to Law of Conservation of Energy) that you could set the Kinetic Energy equal to EPE. (1/2)mv^2 + (1/2)kx^2= (1/2)mv2^2 + (1/2)kx2^2 which reduces to (1/2)mv^2= (1/2) k(-Y2) I am using -Y to denote the compression of the spring if I plug in and solve (1/2)(6kg)(1.2m/s ^2)= (1/2) (4)(Y2) I get 1.341640786 m as the amount of compression. However, this answer is wrong. Can someone tell me what I did wrong?