1. The problem statement, all variables and given/known data A horizontal spring, of force constant 12 N/m is mounted at the edge of a lab bench to shoot marbles at targets on the floor 93.0 cm below. A marble of mass 8.3 X 10 ^ -3 kg is shot from the spring, which is initially compressed a distance of 4.0 cm. How far does the marble travel horizontally before hitting the floor? 2. Relevant equations E-elastic = 1/2kx^2 E-gravity = mgy E-kinetic = 1/2mv^2 3. The attempt at a solution The given information: m = 8.3 X 10 ^ -3 kg k = 12 N/m x = 4.0 cm --> 0.04 m delta Y = 93 cm --> 0.93 m In the start, the elastic energy and the kinetic energy should be the same. So for some reason, I think I have to find the velocity. Ee = Ek 1/2kx^2 = 1/2mv^2 1/2 (12) (0.04)^2 = 1/2 (8.3 X 10 ^ -3)v^2 0.0096 = 0.00415 X v^2 v^2 = 2.31 v= 1.52 m/s So now that I have velocity, I think I can find the horizontal distance. But I don't know what to do now. Can anyone please help me? Thanks. IMPORTANT NOTE: Our teacher told us that we cannot use the equation delta X = vi^2 / g X sin2theta. So please anyone help me in doing in this question without the use of this projectile motion equation.