# Homework Help: Acceleration Formula Question

1. Jan 17, 2005

### 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.

2. Jan 17, 2005

### 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.

3. Jan 17, 2005

### thomasrules

hm,mmmmmmm

4. Jan 17, 2005

### thomasrules

how do i find the distance from core to satelite

5. Jan 17, 2005

### dextercioby

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

Daniel.

6. Jan 17, 2005

### 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.

7. Jan 18, 2005

### futb0l

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?