question_answer

A block is at rest on an inclined plane making an angle \[\alpha \] with the horizontal. As the angle \[\alpha \] of the incline is increased, the block starts slipping when the angle of inclination becomes \[\theta \]. The coefficient  of static friction between the block and the surface of the inclined plane is or             A body starts sliding down at an angle \[\theta \] to horizontal. Then coefficient of friction is equal to            [CBSE PMT 1993]            

A)                         \[\sin \theta \]              

B)                         \[\cos \theta \]            

C)                         \[\tan \theta \]            

D)                         Independent of \[\theta \]