Question

A satellite is orbiting close to the surface of the earth then its speed is

Answer 1

Let's consider that mass of satellite is m , mass of the the earth is M, radius of the earth is R and acceleration due to gravity is g.

when the satellite is orbiting close to the surface of the earth ,
centripetal force = weight of satellite on earth's surface

or, mv²/R = mg

or, v² = gR

hence, v = $\sqrt{gR}$

hence, speed of satellite is $\sqrt{gR}$