Rankers Physics

Gravitational Potential Energy: Practice Problem & Solution

The work done to raise a mass $m$ from the surface of the earth to a height $h$, which is equal to the radius of the earth, is: (2019)
$mgR$
$2mgR$
$\frac{1}{2}mgR$
$\frac{3}{2}mgR$

Solution Explained:

To solve this problem, we apply the core principles of Gravitational Potential Energy. Understanding the underlying formula is key to arriving at the correct answer below:

Work done $W = \Delta U = \frac{mgh}{1+h/R}$. Substituting $h = R$, we get $W = \frac{mgR}{1+1} = \frac{1}{2}mgR$.

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