The motion of planets in the solar system is governed by which of the following conservation laws?

$A$ satellite is orbiting just above the surface of the earth with period $T$. If $d$ is the density of the earth and $G$ is the universal constant of gravitation,the quantity $\frac{3 \pi}{G d}$ represents :

$A$ satellite is orbiting at a distance $r$ from the center of a planet with an angular momentum $L$. If the distance is increased to $16r$,what will be the new angular momentum?

The time period of a satellite,revolving above earth's surface at a height equal to $R$ will be (Given $g = \pi^2 \ m/s^2$,$R =$ radius of earth).

If $L$ is the angular momentum of a satellite revolving around the Earth in a circular orbit of radius $r$ with speed $v$,then .........

The Earth moves around the Sun in an elliptical orbit as shown in the figure. The ratio $OA/OB = x$. The ratio of the speed of the Earth at $B$ to that at $A$ is nearly