By conservation of energy, the kinetic energy of the body just before it hits the floor is mv2i/2=mghi, so its velocity is vi=√2ghi. The coefficient of restitution ...By conservation of energy, the kinetic energy of the body just before it hits the floor is mv2i/2=mghi, so its velocity is vi=√2ghi. The coefficient of restitution is just the square root of the ratio of the rebound height to the initial height. 1