Question

A force acts on a body and displaces it by a distance S in a direction at an angle $\theta$ with the direction of force. What should be the value of $\theta$ to get the maximum positive work?

Answer 1

Work done by a force $W=FS\cos \theta$
where $\theta$ is the angle between force $F$ and displacement $S$.
Work done is maximum and positive when $\cos \theta =1$
$⟹\theta =0^o$
Thus displacement of the body must be in same direction as that of force to get the maximum positive work.