Question

Calculate height of a satellite from surface of earth if its critical velocity is 4 km /sec

Answer 1

particular satellite can have only one speed when in orbit around a particular body at a given distance because the force of gravity doesn’t change. So what’s that speed? You can calculate it with the equations for centripetal force and gravitational force. For a satellite of a particular mass, m1, to orbit, you need a corresponding centripetal force:

This centripetal force has to come from the force of gravity, so

You can rearrange this equation to get the speed:

Human-made satellites typically orbit at heights of 400 miles from the surface of the Earth (about 640 kilometers, or 6.4 × 105 meters). What’s the speed of such a satellite? All you have to do is put in the numbers:

This converts to about 16,800 miles per hour.