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

A satellite of mass $m$ is in circular orbit of radius $3 R_E$ about earth (mass of earth $M_{E}$, radius of earth $R_{E}$). How much additional energy is required to transfer the satellite to an orbit of radius $9 R_{E}$?

Correct formula for height of a satellite from earths surface is :

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 statements is true?

The masses and radii of the earth and moon are $\left({M}_{1}, {R}_{1}\right)$ and $\left({M}_{2}, {R}_{2}\right)$ respectively. Their centres are at a distance ' ${r}$ ' apart. Find the minimum escape velocity for a particle of mass ' ${m}$ ' to be projected from the middle of these two masses: