$A$ particle moves in a circular orbit of radius $r$ under a central attractive force $F = -\frac{k}{r}$,where $k$ is a constant. The periodic time of this motion is proportional to:

If the mass of a satellite is doubled and the time period remains constant,the ratio of the orbital radii in the two cases will be:

The relay satellite transmits the $T.V.$ programme continuously from one part of the world to another because its

Two satellites $A$ and $B$ go round the planet $P$ in circular orbits having radii $4 R$ and $R$ respectively. If the speed of the satellite $A$ is $3 v$,the speed of satellite $B$ will be ...........

Two particles of identical mass are moving in circular orbits under a potential given by $V(r) = K r^{-n}$,where $K$ is a constant. If the radii of their orbits are $r_1$ and $r_2$ and their speeds are $v_1$ and $v_2$,respectively,then:

Suppose an astronaut throws a spoon out of a spacecraft. Will the spoon fall to the Earth?