Question

The velocity with which a projectile must be fired so that it escapes earth's gravitation does not depend on

(a) mass of the earth

(b) mass of the projectile

(c) radius of the projectile's orbit

(d) gravitational constant

Answer 1

Correct option (b) mass of the projectile

Explanation :

For a projectile to leave the gravitational field of the earth, its kinetic energy would be at least equal to its potential energy. That is

where G is the universal gravitational constant, M is the mass of the earth and R is the radius of the earth. Hence the escape velocity of a projectile is independent of its own mass.