A marble is allowed to roll down an inclined plane from a fixed height. At the foot of the inclined plane, it moves on a horizontal surface (a) covered with silk cloth (b) covered with a layer of sand and (c) covered with a glass sheet. On which surface will the marble move the shortest distance. Give reason for your answer.

The marble will move the shortest distance on the layer of sand because the silk cloth and glass sheet will exert lesser maximum friction whereas the sand (being more rough) exert maximum friction against the motion.


20