WBJEE 2014 Physics Solved Paper

To determine the coefficient of friction between a rough surface and a block, the surface is kept inclined at 45° andthe block is released from rest. The block takes a time t in moving a distance d.The rough surface is then replacedby a smooth surface and the same experiment is repeated. The block now takes a time t/2 in moving down thesame distance d. The coefficient of friction is