Let's say I have a pinball (solid sphere) with a given mass and radius, and it is held back at a certain distance from equilibrium on a spring. The spring constant k is given, and the ball is then fired onto the pinball machine surface, which is tilted. How would I find the maximum height the pinball rolls to (above its initial location.)? I know I should use energy conservation, but is this the correct formula: 0.5m(vi^2) + 0.5k(yi^2) = 0.5m(vf^2) + 0.5k(yf^2)? Would yf be the same as the height at which the pinball machine is tilted or is it the distance from the spring equilibrium the pinball travels to? Any help is appreciated!