Question

A small block of mass m is kept on a rough inclined surface of inclination θ fixed in an elevator.

Answer 1

Distance travelled by the 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 vtsin^2θ

Thus, the work done by the force of friction in time t will be mgvtsin^2θ

Answer 2

Answer:

hope this helps u mate,.......,