If $W_1, W_2$ and $W_3$ represent the work done in moving a particle from $A$ to $B$ along three different paths 1,2 and 3 (as shown in fig) in the gravitational field of the point mass ' $m$ '. Find the correct relation between ' $W_1$ ', ' $W_2$ ' and ' $W_3$ '

The kinetic energy of a revolving satellite (mass $m$ ) at a height equal to thrice the radius of the earth $(R)$ is

A body is projected vertically from the surface of the earth of radius ' $R$ ' with velocity equal to half of the escape velocity. The maximum height reached by the body is