Write the equation for the orbital velocity of a satellite revolving very close to the surface of the Earth.

(N/A) The orbital velocity $v_o$ of a satellite at a distance $r$ from the center of the Earth is given by $v_o = \sqrt{\frac{GM}{r}}$.
For a satellite revolving very close to the surface of the Earth,the distance $r$ is approximately equal to the radius of the Earth $R_e$ (i.e.,$r \approx R_e$).
Substituting $r = R_e$ into the formula,we get $v_o = \sqrt{\frac{GM}{R_e}}$.
Since the acceleration due to gravity $g$ at the surface of the Earth is given by $g = \frac{GM}{R_e^2}$,we can write $GM = gR_e^2$.
Substituting this into the orbital velocity equation,we get $v_o = \sqrt{\frac{gR_e^2}{R_e}} = \sqrt{gR_e}$.