To do work is it mandatory to have force and displacement in the same direction?

 

Dear Student,
It is not mandatory to have force and displacement in the same direction to do work.
$work done, W=\left|\overrightarrow{F}\right|.\left|\overrightarrow{S}\right|\cos \theta$
Therefore, the amount of work done depends on the magnitude of force applied, the magnitude of displacement and the angle between force and displacement.
1) If the force and displacement are in the same direction that is when $\theta = 0°$ then the work done is positive.
2)If the force and the displacement are in opposite directions that is when $\theta = 180°$then the work done is negative.
We can say that to do a work the angle between force and displacement can take any value except $\theta = 90°$, as for $\theta = 90°$ the work done is 0. Therefore to do a work it is not mandatory to have force and dispalcement in the same direction.
Regards