# Centripetal Acceleration of Satellite

## Homework Statement

Hi, I am stuck on this question:
A satellite of mass 1200 kg is in orbit around the Earth at a distance of 22000 km from the centre of the Earth.
Calculate the magnitude of the centripetal acceleration of the satellite at this distance.

## The Attempt at a Solution

I did:
mv^2/r= GMm/r^2
so v= square root of GM/r
v= square root of 6.67 x10^-11 x 6.0 x 10^24/ 22000 x 10^3
this gave me=
4.266x 10^-3 m/s but the answer at the back is 0.83 m/s^2, can someone please explain to where i went wrong.

Thanks[/B]

vela
Staff Emeritus
Homework Helper

Hi, I've reread it many time, but i still feel confused

vela
Staff Emeritus
Homework Helper
What's it asking you to find? What did you actually calculate?

What's it asking you to find? What did you actually calculate?
Oh I see what you mean, are you implying that I solved centripetal velocity instead of centripetal acceleration?

vela
Staff Emeritus
Homework Helper
Essentially. You solved for what's sometimes called the tangential velocity, not centripetal velocity.

Essentially. You solved for what's sometimes called the tangential velocity, not centripetal velocity.
So does this mean I consider gravity of Earth as my centripetal velocity and therefore:
g= GM/r^2, but i still have a query, if you could kindly clear this up for me, why can't we use the centripetal formula in this question.

vela
Staff Emeritus