A satellite $S$ moves around a planet $P$ in an elliptical orbit as shown in figure. The ratio of the speed of the satellite at point $a$ to that at point $b$ is 

A geo-stationary satellite is orbiting the earth at a height of $6 R$ above the surface of earth, $R$ being the radius of earth. The time period of another satellite at a height of $2.5 R$ from the surface of earth is

In a satellite if the time of revolution is $T$, then $P E$ is proportional to ..........

A body weighs $700\,gm\,wt.$ on the surface of the earth. How much will it weigh on the surface of a planet whose mass is $\frac {1}{7}$ and radius half of that of the earth ....... $gm\, wt$

Which of the following graph represents the variations of acceleration due to gravity $(g)$ with distance $r$ from the centre of earth?

A satellite can be in a geostationary orbit around a planet at a distance $r$ from the centre of the planet. If the angular velocity of the planet about its axis doubles, a satellite can now be in a geostationary orbit around the planet if its distance from the centre of the planet is