A block of mass m =11.7 kg is to be pushed a distance of s=4.65 m. Assuming frictionless surface. Calculate the work done in applying a force parallel to the incline to push the block up at a constant speed. (Take, g=9.8 `ms^(-2)`)

Options

A. 328 J
B. 656 J
C. 164 J
D. 530 J

Answer

A

Explanation

(a) Given, m=11.7 kg, s=4.65 m, h=2.86 m
From the figure, sin `theta=(2.86)/(4.65)=0.61`
Also, component of mg along the incline is mg `sin theta`.
`:. "Work done by this force" =mg sin theta.s`
`W_(F)+W_(g)=DeltaKE=0,W_(g)=-mgh`
`=11.7xx9.8xx0.61xx4.65`
`=11.7xx9.8xx2.86=327.9=328J`