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

1. When the object is moved from point A to point B in the same horizontal plane, there is no change in height.
2. Displacement is in the horizontal direction.
3. The force applied by the force of gravity is perpendicular to the direction of the displacement of the object.
4. The work done due to gravity is given by the expression $\mathrm{mass}\times \mathrm{acceleration}\mathrm{due}\mathrm{to}\mathrm{gravity}\times \mathrm{height}$.
5. The height, in this case, is zero, so the work done will also be zero.