Sol.

Two force are acting on the skater as he leans towards the centre of the circle; his own weight and the reaction of the ice-track, which has a horizontal component and is therefore inclined at an angle. The horizontal component of the ice-track’s reaction (fig.) comes into play as a result of the fact that the skater, gliding along his path, does not glide in a perpendicular position. This horizontal component is analogous to the force of friction which acts on the coin in problem 4.

The resultant of the weight of the skater P and the inclined reaction of the ice-track R is a force acting horizontally and imparting to the skater the centripetal acceleration necessary to motion in a circle.