An asteroid is moving directly towards the centre of the earth. When at a distance of 10 R (R is the radius of the earth) from the earths centre , it has a speed of 12 km/s . Neglecting the effect of earths atmosphere, what will be the speed of the asteroid when it hits the surface of the earth (escape velocity from the earth is 11.2 km/s ) ? Give your answer to the nearest integer in kilometer/s _______ .
A body is moving in a low circular orbit about a planet of mass M and radius R. The radius of the orbit can be taken to be R itself. Then the ratio of the speed of this body in the orbit to escape velocity from the planet is:
The value of the acceleration due to gravity is at a height ( radius of the earth) from the surface of the earth. It is again equal to at a depth below the suface of the earth. The ratio equals :