Question

The mass of the earth is $6.0\times 10^{24}kg.$ The potential energy of a body of mass $50kg$ at a distance of $6.3\times 10^{9}m$ from the centre of the earth is

• A. $-3.23\times 10^{9}J$
• B. $-3.19\times 10^{6}J$
• C. $-2.5\times 10^{6}J$
• D. $-4.0\times 10^{11}J$

Answer 1

Answer: (B)

Here, mass of the earth $(M)=6.0\times 10^{24}kg$, Mass of the body $(m)=50kg$ and distance $(r)=6.3\times 10^{9}m$ Potential energy,
$U=-\frac{GMm}{r}$
$=-\frac{\left(6.7\times 10^{-11}\right)\times \left(6.0\times 10^{24}\right)\times 50}{6.3\times 10^9}=-3.19\times 10^{6}J$