In a satellite,if the time of revolution is $T$,then the potential energy $(PE)$ is proportional to ..........

$A$ satellite of mass $200 \,kg$ revolves around a planet of mass $5 \times 10^{30} \,kg$ in a circular orbit of radius $6.6 \times 10^6 \,m$. Binding energy of the satellite is .............. $J$

$A$ satellite orbits the Earth at a height of $400 \; km$ above the surface. How much energy must be expended to rocket the satellite out of the Earth's gravitational influence? (Mass of the satellite $= 200 \; kg$; mass of the Earth $= 6.0 \times 10^{24} \; kg$; radius of the Earth $= 6.4 \times 10^{6} \; m$; $G = 6.67 \times 10^{-11} \; N m^{2} kg^{-2}$)

If a particle of mass $m$ is moving in a horizontal circle of radius $r$ with a centripetal force $(-k/r^2)$,the total energy is

$A$ skylab of mass $m \ kg$ is first launched from the surface of the earth into a circular orbit of radius $2R$ (from the centre of the earth) and then it is shifted from this circular orbit to another circular orbit of radius $3R$. The minimum energy required to shift the lab from the first orbit to the second orbit is:

When a satellite going round the Earth in a circular orbit of radius $r$ and speed $v$ loses some of its energy,then $r$ and $v$ change as: