Question

orce of 40 N is required to pull up cylindrical barrel of mass 2.5 kg through a distance of 7.5 m along the
inclined plane as shown in diagram alongside. Calculate.
(a) Force of gravity acting on the barrel. (Take g = 10 ms?)
(b) Work done by the force in pulling body along the inclined plane
(c) Work done against the force of gravity.
​

Answer 1

Given Mass of the object m=50kg and displacement s=100m.

Now frictional force f=μN where μ=coefficient of friction and N= normal force

We know N=mg; where g=acceleration due to gravity =10 m/s

2

N=50×10=500N.

Thus frictional forcef=500μ

Again work done by frictional forceW

f

=fscosθ where s= displacement =100 m and θ=0

0

ThereforeW

f

=500μ×100=50μkJ