Compare the gravitational potential at the center $O$ for the given arcs,each having mass $M$ and radius $R$.

Four spheres each of mass $m$ form a square of side $d$ (as shown in the figure). $A$ fifth sphere of mass $M$ is situated at the centre of the square. The total gravitational potential energy of the system is

$A$ person brings a mass of $1 \ kg$ from infinity to a point $A.$ Initially,the mass was at rest but it moves at a speed of $3 \ m/s$ as it reaches $A.$ The work done by the person on the mass is $-5.5 \ J.$ The gravitational potential at $A$ is $:$ (in $J/kg$)

$A$ particle of mass $10\, g$ is kept on the surface of a uniform sphere of mass $100\, kg$ and radius $10\, cm$. Find the work to be done against the gravitational force between them to take the particle far away from the sphere (you may take $G = 6.67 \times 10^{-11}\, Nm^2 / kg^2$).

$A$ body of mass $m$ rises to a height $h = R/5$ from the earth's surface,where $R$ is the earth's radius. If $g$ is the acceleration due to gravity at the earth's surface,the increase in potential energy is:

Gravitational potential difference between the surface of a planet and a point situated at a height of $20\,m$ above its surface is $2\,J/kg$. If the gravitational field is uniform,then the work done in taking a $5\,kg$ body to a height of $4\,m$ above the surface will be ........ $J$.