Question

A gardener pushes a lawn roller through a distance of 20 m. If he applies a force of 20 kg-wt in a direction inclined at ${60}^{\circ }$ to the ground, find the work done by him.

Answer 1

Force aplied, F = 20 kg-wt = $20\times 9.8N=196N$
This force is applied at an angle ${60}^{\circ }$ with the ground.
So, the component of the force that is responsible for displacement of the lawn roller is $Fcos{60}^{\circ }=196\times 0.5=98N$
So, work done $=98\times 20=1960J$