1. The problem statement, all variables and given/known data A block is on a frictionless incline. A block at the bottom of the incline is resting up the incline against a spring. The first block is released. The blocks stick and compress the spring. What is the common velocity immediately after collision? 2. Relevant equations Kinetic energy of the two blocks + potential energy of blocks = potential energy of spring 3. The attempt at a solution I am not concerned with solving this equation for the velocity. I am just concerned with understanding how to get to this equation. My exam useful equations study sheet shows that kinetic initial+ potential initial = kinetic final + potential final.