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 $\frac{x}{5} \frac{GM^2}{R}$,where $x$ is .......... (Round off to the Nearest Integer). ($M$ is the mass of earth,$R$ is the radius of earth,$G$ is the gravitational constant)

The $S.I.$ unit of gravitational potential is

What is the total energy of a system of two masses at an infinite distance from each other?

The gravitational potential energy of a body of mass $m$ at a distance $r$ from the center of the Earth is $U$. Express the weight of the body at this point in terms of $U$.

Four particles each of mass $m$ are placed at the vertices of a square of side $l.$ The potential energy of the system is

The particles $A$ and $B$ of mass $m$ each are separated by a distance $r$. Another particle $C$ of mass $M$ is placed at the midpoint of $A$ and $B$. Find the work done in moving $C$ to a point equidistant $r$ from $A$ and $B$ without acceleration. ($G$ is the gravitational constant and only gravitational interaction between $A, B$ and $C$ is considered.)