1. The minimum velocity with which a both’ should he thrown vertically upwards from the surface of the Earth so that it escapes the Earth ‘s gravitational field, is called the escape velocity (ve) of the body.
2. As the gravitational force due to Earth becomes zero at infinite distance, the object has to reach infinite distance in order to escape.
3. Let us consider the kinetic and potential energies of an object thrown vertically upwards with escape velocity ve.
4. On the surface of the Earth,
5. The kinetic energy of the object will go on decreasing with time as it is pulled back by Earth’s gravitational force. It will become zero when it reaches infinity. Thus, at infinite distance from the Earth,
6. As energy is conserved
