Question

A force of 45 N acts on a body and moves it a distance of 3m on a horizontal surface. Calculate the work done if the direction of force is at an angle of 60° to the horizontal surface. Derive the relation between kWh and joule.​

Answer 1

Explanation:

Force acting on the body = 10 kgf = 10 x 10 N = 100 N

Displacement, S=0.5 m

Work done= force x displacement in the direction of force

(i)W =F x S

W = 100 x 0.5= 50 J

(ii)Work = force x displacement in the direction of force

W = F x S cos

W = 100 x 0.5 cos60o

W= 100 x0.5 x 0.5(cos60o=0.5)

W=25 J

(iii)Normal to the force:

Work = force x displacement in the direction of force

W = F x S cos

W = 100 x 0.5 cos90o

W= 100 x 0.5 x 0 =0 J(cos90o =0)