# Satellite velocity

1. Oct 22, 2010

### pb23me

1. The problem statement, all variables and given/known data[/b]
calculate the velocity of a satellite 3600 km above the surface of the earth.

2. Relevant equations
Fnet= mg=ma
mg=ma
g=V2/r
r=3600000

3. The attempt at a solution 5940 m/s im pretty sure this is correct just want to make sure.

2. Oct 22, 2010

### Xerxes1986

Looks good to me as long as you plugged in all the right values

3. Oct 22, 2010

### Filip Larsen

Two things you need to include in your calculation:
1) at 3600 km above the surface of Earth, the acceleration due to gravity is not same as at the surface.
2) The radius in the circular motion equation is not 3600 km.
The correct value is a bit more than what you got.

4. Oct 23, 2010

### Xerxes1986

You are right....but the equations are right, and as we all know that is all that matters once you start grad school :P haha

5. Oct 23, 2010

### gau_physics

Just equate centripetal acceleration to the gravitational force at that height.
Better just remember the formula instead of deriving each time -

v = sq root (GM/r)

where G = grav constant, M= mass of earth, r = distance from centre of earth