A cylindrical metal rod of radius r and a substantial length h is mounted vertically on the Earth's surface at the Equator. A small metal ball of 2r radius has a through hole of radius r and is allowed to fall freely due to gravitational pull using the cylindrical rod as a guide (rail).The rod goes thrugh the ball. At the base there is a small horizontal metal plate on which the ball bounces. The question is ,considering elastic oscilations due to gravitational fall what other forcess will take place? (Imagine zero friction).