Question

If the gravitational potential energy at infinity is assumed to be zero, the potential energy at distance $\left(R_{E}+h\right)$ from the centre of the earth is

• A. $PE =\frac{G m M_{E}}{\left(R_{E}+h\right)}$
• B. $PE =\frac{-G m M_{E}}{\left(R_{E}+h\right)}$
• C. $PE =m g h$
• D. $PE =\frac{-Gm M_{E}}{2\left(R_{E}+h\right)}$

Answer 1

Answer: (B)

Gravitational potential energy of a body of mass $m$ at a distance $r$ from the centre of the earth is
$=-\frac{G m M_{E}}{r}$
$\because r =R_{E}+h $
$\therefore PE =-\frac{G m M_{E}}{\left(R_{E}+h\right)}$