What is meant by escape velocity? Write the relation between escape velocity and orbital velocity.

Escape velocity is the lowest velocity which a body must have in order to escape the gravitational attraction of a particular planet or other object.

The relation between escape velocity and orbital velocity is given by V${}_e$ = $\sqrt{2}$V$o$ where V${}_e$ is the escape velocity and V${}_o$ is the orbital velocity. Thus the escape velocity is root-two times the orbital velocity.