# Acceleration Formula Question

thomasrules
i don't know what formula to use..... I know that F=Gm1m2/d^2

An Earth satellite travels in a circular orbit of radius four times the Earth's radius. Calculate its acceleration in m/s^2.

## Answers and Replies

Ryoukomaru
You can solve it by looking at the acceleration due to gravity on the earths surface and the ratio between Core to Surface :: Core to Satellite orbit. Since F is inversely proportional to distance^2, it should be 16 times weaker.

thomasrules
hm,mmmmmmm

thomasrules
how do i find the distance from core to satelite

Homework Helper
The problem says it's 4 times more than the Earth's radius...

Daniel.

Ryoukomaru
You are told in the question that it was 4 times the earths radius. You dont need the actual figures. The ratio 4:1 is enough to solve the question. But you might also try using that formula to calculate the force on the satellite. But you cant use it if you dont have the mass of the satellite. And from what you said in ur first post, i deduce that ur not given that.

PS. heh he beat me. I type too much. Well, isnt it just the centripetal acceleration of the satellite??
Because then you can take the orbital speed and square it then divide it by 4r?