Orbital speed of a satellite.

1. Oct 19, 2008

JohnnyB212

1. The problem statement, all variables and given/known data

A satellite is in circular orbit above the Earth at an altitude of 7000 km. What is the orbital speed of the satellite?

2. Relevant equations

Well, knowing that the mass of earth of 5.98 X 10^24 kg

And the radius of earth is 6.38 x 10^6 m

What equation do I start with here? The "speed" portion is whats getting me.

2. Oct 19, 2008

mgb_phys

Orbit means that the gravitational force inward and the centrifugal force outward are balanced. The centrifugal force depends on the angular speed and this with the radius will give you the speed.

3. Oct 20, 2008

Epsillon

First you need to find the Fg and that would be using the GM/R^2 formula once u have Fg you can get v using mv^2/r