A long thin board lies on a smooth table close to a smooth wall. A cylinder rolls along a board without slipping in a direction perpendicular to the wall (Figure). The cylinder hits the wall perfectly elastically. Determine the fraction of the initial kinetic energy converted into heat during friction between the cylinder and the board by the time the cylinder rolls off the board. The mass of the cylinder is equal to half the mass of the board. Ignore rolling friction.

Answer. Format gif