Question:
If one wants to remove all the mass of the earth to infinity in order to break
it up completely. The amount of energy that needs to be supplied will be $\frac{x}{5} \frac{\mathrm{GM}^{2}}{\mathrm{R}}$ where $\mathrm{x}$ is___
(Round off to the Nearest Integer)
( $M$ is the mass of earth, $R$ is the radius of earth, $G$ is the gravitational constant)
Solution:
(3)
Energy given $=\mathrm{U}_{\mathrm{f}}-\mathrm{U}_{\mathrm{i}}$
$=0-\left(-\frac{3 \mathrm{GM}^{2}}{5} \frac{\mathrm{R}}{\mathrm{R}}\right)$
$=\frac{3}{5} \frac{\mathrm{GM}^{2}}{\mathrm{R}}$
$x=3$