When a satellite moves around the earth in a certain orbit,the quantity which remains constant is:

$A$ planet of mass $m$ moves around the Sun along an elliptical path with a period of revolution $T$. During the motion,the planet's maximum and minimum distance from the Sun is $R$ and $\frac{R}{3}$ respectively. If $T^2 = \alpha R^3$,then the magnitude of constant $\alpha$ will be

The time period of a geostationary satellite is $24 \; h$,at a height $6 R_{E}$ ($R_{E}$ is the radius of the Earth) from the surface of the Earth. The time period of another satellite whose height is $2.5 R_{E}$ from the surface will be:

$A$ satellite $A$ of mass $m$ is at a distance of $r$ from the centre of the earth. Another satellite $B$ of mass $2m$ is at a distance of $2r$ from the earth's centre. Their time periods are in the ratio of:

$A$ satellite moves in a circle around the earth. The radius of this circle is equal to one half of the radius of the moon's orbit. The satellite completes one revolution in

The time period of a satellite in a circular orbit of radius $R$ is $T$. The period of another satellite in a circular orbit of radius $9R$ is............ $T$.