Ans. When the ball is at the mean position O i.e. at the centre of the bowl, net force acting on the ball is zero. Now if we bring the ball at position A and then release it, the ball will start moving towards the mean position O and the extreme position B due to the restoring force caused by its weight. The ball continues its motion about the mean position O. This to and fro motion about the mean position O continues till all the energy is lost due to friction. Thus, to and fro motion of the ball about a fixed position placed in a bowl is SHM.