Question

A mass of $10kg$ is at a point $A$ on a table. It is moved to a point $B$. If the line joining $A$ and $B$ is horizontal what is the work done on the object by the gravitational force? Explain your answer.

Answer 1

$w=\overrightarrow{f}\times \overrightarrow{s}\cos \theta$

$w=mg\times \overrightarrow{s}\times \cos {90}^{\circ }$

$w=0(as\cos {90}^{\circ }=0)$

Work done by gravitational force will be zero because when force is applied perpendicular to the surface the work done is zero.