Question

If a body of mass $m$ falls through a height$h$. Establish an equation for the work done by the gravity.

Answer 1

Work done by gravity:

1. Let a body of mass m fall through a height h, either directly or through an inclined plane e.g. a hill, slope, or staircase.
2. The force of gravity$\left(F\right)$ on the body is $F=mg$, acting vertically downwards.
3. The displacement$\left(s\right)$ is in the direction of force (i.e., vertical). So, $s=h$.
4. Therefore the work done$\left(W\right)$ by the force of gravity is $Workdone=Force\times Displacement$
   $\Rightarrow W=mgh$
5. Hence, the equation for the work done by gravity is $W=mgh$.