Question

The change in potential energy, when a body of mass $m$ is raised to a height $nR$ from the earth's surface is $(R=$ radius of earth$)$

• A. $mgR\left(\frac{n}{n-1}\right)$
• B. $nmgR$
• C. $mgR\left(\frac{n^2}{n^2+1}\right)$
• D. $mgR\left(\frac{n}{n+1}\right)$

Answer 1

Answer: (D)

$mgR\left(\frac{n}{n+1}\right)$

$△U=U_f-U_i=-\frac{GMm}{nR+h}-(-\frac{GMm}{R})$
$=\frac{n}{n+1}.\frac{GMm}{R}=\frac{n}{n+1}mgR$