A body of mass $m$ is placed on the earth’s surface. It is taken from the earth’s surface to a height $h = 3R$. The change in gravitational potential energy of the body is

A stationary body on a surface of earth have negative energy -What it indicate (Negative energy indicates that body is bind with earth. If a body give this energy or it will be given positive energy, it goes to at infinity).

Correct formula for height of a satellite from earths surface is :

A body of mass $m$ is moving in a circular orbit of radius $R$ about a planet of mass $M$. At some instant, it splits into two equal masses. The first mass moves in a circular orbit of radius $\frac{R}{2}$ , and the other mass, in a circular orbit of radius $\frac{3R}{2}$. The difference between the final and initial total energies is

With what velocity should a particle be projected so that its height becomes equal to radius of earth?