Mass 1 with a mass of 28.5 kg starts at rest at the top of a frictionless from a height of 17 meters. It then slides down the incline and moves over a horizontal frictionless surface and collides inelastically (head on) with mass 2 which is of unknown mass. After the collision, the total kinetic energy of both masses is 60% of the initial total kinetic energy of both masses before the collision. What is the amount of mass 2 in kg?

Question

Mass 1 with a mass of 28.5 kg starts at rest at  the top of a frictionless from a height of 17 meters.  It then slides down the incline and moves over a horizontal frictionless surface and collides inelastically (head on) with mass 2 which is of unknown mass.  After the collision, the total kinetic energy of both masses is 60% of the initial total kinetic energy of both masses before the collision.  What is the amount of mass 2 in kg?