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Grade 12th passMechanics

A small block of mass m is kept on rough inclined surface of inclination theta fixed in a elevator goes up wish a uniform velocity v and the block does slide on the wedge. The work done by force of friction on the block in time t will be

Profile image of Udit Thacker
7 Years agoGrade 12th pass
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1 Answer

Profile image of Arun
7 Years ago
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