The time period of polar satellites is about ..........

An earth satellite of mass $m$ revolves in a circular orbit at a height $h$ from the surface of the earth. $R$ is the radius of the earth and $g$ is acceleration due to gravity at the surface of the earth. The velocity of the satellite in the orbit is given by

Two satellites $A$ and $B$ move around the Earth in the same orbit. The mass of $A$ is twice the mass of $B$. The quantity which is the same for the two satellites will be:

Spaceman Fred's spaceship (which has negligible mass) is in an elliptical orbit about Planet Bob. The minimum distance between the spaceship and the planet is $R$; the maximum distance between the spaceship and the planet is $2R$. At the point of maximum distance,Spaceman Fred is traveling at speed $v_0$. He then fires his thrusters so that he enters a circular orbit of radius $2R$. What is his new speed?

$A$ satellite is revolving around the Earth in a circular orbit at a uniform speed $v$. If the gravitational force suddenly disappears,the speed of the satellite will be ..............

$A$ satellite of mass $M$ is in a circular orbit of radius $R$ about the center of the Earth. $A$ meteorite of the same mass $M$,falling towards the Earth,collides with the satellite completely inelastically. The speeds of the satellite and the meteorite are the same,just before the collision. The subsequent motion of the combined body will be: