Ablock is placed on the top of an inclined plane of inclination 6 kept on the floor of a lift which is moving down with an acceleration a. the coefficient of fr

Ablock is placed on the top of an inclined plane of inclination 6 kept on the floor of a lift which is moving down with an acceleration a. The coefficient of friction between the block and the incline so that the block moves down with a constant velocity is, is (a) u = tan 6 (b) u =- tan 6 ()-1-tan (d) = tan 0