1. The problem statement, all variables and given/known data The ball launcher in a pinball machine has a spring that has a constant of 1.2 N/cm. The surface on which the ball moves is inclined 10 degrees with respect to the horizontal. If the spring is initially compressed 5.0 cm, find the launching speed of a 100g ball when the plunger is released. 2. Relevant equations W = .5kx^2 mgh + .5kx^2 + .5mv^2 = mghf + .5kxf^2 + .5mvf^2 3. The attempt at a solution first i converted the spring constant 1.2 N/cm * 100cm/m = 120 N/m next i found PE(spring) .5kx^2 = .5(120N/m)(.05m)^2 = .15 J then i used the mechanical energy eq...i canceled the unnecessary terms and got: .5kx^2 + .5mv^2 = mgh(f) and when i solve for V(initial) i get: ((mgh(f) - .5kx^2 )/(.5m))^.5 but then i dont know the distance which the ball travels so i cant use this equation and also i know the 10 degrees has to factor in somewhere, but where? is it part of the potential energy of the string? or does it affect the initial velocity? or both?