A carpet of mass M made of inextensible material is rolled along its length in the form of a cylinder of radius R and is kept on a rough floor. The carpet starts unrolling without sliding on the floor when a negligibly small push is given to it. Loss in potential energy due to unrolling radius changes from R to R2 is
A carpet of mass M is rolled along its length in the form of a cylinder of radius R and kept on a rough floor. The decrease in potential energy, if the carpet is unrolled without sliding to a radius R2 is equal to