Orbital velocity is the velocity given to artificial satellite so that it may start revolving around the earth.
Expression for orbital velocity:
Consider, a satellite of mass 'm' is revolving around the earth in a circular orbit of radius 'r', at a height 'h' from the surface of the earth. Let 'M' be the mass of the earth and 'R' be the radius of the earth.
Therefore, r = R + h
The centripetal force that is required to revolve the satellite = mv02/r
where,
v0 is orbital velocity.
Orbital velocity is produced by the gravitational force between the earth and the satellite =GMm/r2
Therefore,
where g is the acceleration due to gravity.
So,
Let g' be the acceleration due to gravity in the orbit i.e. at a height h from the surface.
Therefore