What is the minimum energy required to launch a satellite of mass $m$ from the surface of a planet of mass $M$ and radius $R$ in a circular orbit at an altitude of $2R$?

Show the nature of the following graph for a satellite orbiting the earth.

$(a)$ $KE$ versus orbital radius $R$

$(b)$ $PE$ versus orbital radius $R$

$(c)$ $TE$ versus orbital radius $R$

To project a body of mass $m$ from earth's surface to infinity, the required kinetic energy is (assume, the radius of earth is $R_E, g=$ acceleration due to gravity on the surface of earth) :

Two satellites of earth $S_1$ and $S_2$ are moving in the same orbit. The mass of $S_1$ is four times the mass of $S_2$. Which one of the following statement is true ?

Two bodies of masses ${m_1}$ and ${m_2}$ are initially at rest at infinite distance apart. They are then allowed to move towards each other under mutual gravitational attraction. Their relative velocity of approach at a separation distance $r$ between them is