Escape Velocity

A ball thrown upwards always comes back due to the force of gravity. If you throw it with greater force, it goes a little higher but again comes back. Is it possible for an object to escape the pull of the earth? The answer is ‘yes’. The object must acquire what is called the escape velocity. It is defined as the minimum velocity required by an object to escape the gravitational pull of the earth.

The escape velocity depends on the mass of the body it is trying to escape from, because the gravitational pull is proportional to mass. It also depends on the radius of the body, because smaller the radius, stronger is the gravitational force.

It is not that the force of gravity ceases to act when an object is launched with escape velocity. The force does act. Both the velocity of the object as well as the force of gravity acting on it decrease as the object goes up. It so happens that the force becomes zero before the velocity becomes zero. Hence the object escapes the pull of gravity.