The Sun revolves around the galaxy with a speed of $250 \, km/s$ and its radius is $3 \times 10^{4} \, \text{light years}$. The mass of the Milky Way is:

Write the equation for the orbital velocity of a satellite revolving very close to the surface of the Earth.

The distances of two planets $A$ and $B$ from the sun are $r_A$ and $r_B$ respectively. Given that $r_B = 100 r_A$. If the orbital speed of planet $A$ is $v$,then the orbital speed of planet $B$ is:

What is the time period of a satellite orbiting at a height $R$ above the Earth's surface?

$A$ planet of mass $m$ moves in an elliptical orbit around an unknown star of mass $M$ such that its maximum and minimum distances from the star are equal to $r_1$ and $r_2$ respectively. The angular momentum of the planet relative to the centre of the star is

$A$ geostationary satellite is revolving around the Earth. If the radius of the Earth is $R$ and the angular speed of the Earth about its own axis is $\omega$,then the radius of the orbit of the geostationary satellite is ($g =$ acceleration due to gravity).