Question

Gravitational potential difference between surface of a planet and a point situated at a height of $20m$ above its surface is $2joule/kg$. If gravitational field is uniform, then the work done in taking a $5kg$ body of height $4$ meter above surface will be :-

• A. $2J$
• B. $20J$
• C. $40J$
• D. $10J$

Answer 1

The correct option is A $2J$

The potential difference for a distance of $20m$ is $2joule/kg$.

Now work done $=m\times$ potential difference.

Thus work done for a distance of $4m$ for a mass $5kg$, $W=\frac{4}{20}\times 2\times 5$

$⟹W=2J$