At which height from the surface of the Earth does a polar satellite revolve around the Earth?

The gravitational potential energy required to raise a satellite of mass $m$ to a height $h$ above the Earth's surface is $E_1$. Let the energy required to put this satellite into orbit at the same height be $E_2$. If $M$ and $R$ are the mass and radius of the Earth respectively,then the ratio $E_1: E_2$ is:

$A$ satellite is to be placed in an equatorial geostationary orbit around the Earth for communication purposes. The height of such a satellite is $(M_{E} = 6 \times 10^{24} \,kg, R_{E} = 6400 \,km)$.

$A$ satellite of mass $m$ is launched vertically upwards with an initial speed $u$ from the surface of the earth. After it reaches height $R$ ($R =$ radius of the earth), it ejects a rocket of mass $\frac{m}{10}$ so that subsequently the satellite moves in a circular orbit. The kinetic energy of the rocket is ($G$ is the gravitational constant, $M$ is the mass of the earth).

$A$ planet is moving around the sun in an elliptical orbit at different positions $A, B, C, D$. The maximum kinetic energy of the planet is at position:

The radii of circular orbits of two satellites $A$ and $B$ of the earth are $4R$ and $R,$ respectively. If the speed of satellite $A$ is $3V,$ then the speed of satellite $B$ will be ...... $V$.