A small block of mass m kept on a rough inclined surface of inclination 'A' fixed in a elevator.The elevator goes up witha uniform velocity v and the block does not slide on the wedge.The work done by the force of friction in time t will be??

Asked by Malavika Umesh | 18th May, 2015, 06:51: PM

Expert Answer:

 
 
Distance travelled bythe elevator in 't' time is = vt
As the block does not slide on the wedge. So friction force, f= mg sinθ
Angle between d and f is (90 - θ)
Work done by the force friction on the block in time t will be = F.d
That is,
Work, W = Fd cos (90 - θ)
              = mg sin θ . vtsin θ 
             = mg vtsin2θ
Thus, the work done by the force of friction in time t will be mgvtsin2θ

Answered by Yashvanti Jain | 13th Dec, 2017, 06:39: PM