Question
Assertion : No work is done by a force on an object when the point of application of the force does not move.Reason : A small block of mass m is kept on a rough inclined surface of inclination a fixed in an elevator. The elevator goes up with a uniform velocity u and the block does not slide on the wedge.Then the work done by the force of friction on the block in time t will be mgutsin2a.(3) C(4) D