Homework Help: Satelite orbit distance

1. Sep 21, 2012

Feodalherren

1. The problem statement, all variables and given/known data
A 320kg satellite experiences a gravitational force 800N. What is the radius of the satellite's orbit?

2. Relevant equations
G m1m2 / d^2

3. The attempt at a solution
I started with

800N = (G(320kg)(5.98(10^24)kg) / d^2

After some algebra and rounding I ended up with d = 40,000 km. Is that reasonable?

2. Sep 21, 2012

SHISHKABOB

when I put 40,000 km into the original equation and solve for the force I get around 79.77N

what value did you use for G?

3. Sep 21, 2012

Feodalherren

I think the standard for any calculations in classical mechanics is kg and meters. So perhaps if you try 40,000,000m.

I used 6.67 x 10 ^-11 for G.

4. Sep 22, 2012

Feodalherren

Shameless bump. Still need help.

5. Sep 22, 2012

SHISHKABOB

I kept trying again and again but I am getting 12k kilometers

$d = \sqrt{\frac{GMm}{F}}$

yes?

so

$d = \sqrt{\frac{(6.67*10^{-11}N*(\frac{m^{2}}{kg^{2}}))(5.98*10^{24}kg)(320kg)}{800 N}} = 1.26*10^{7} m$

maybe you can point out where our calculations differ? I might be doing something hilariously incorrect.

6. Sep 22, 2012

Feodalherren

No, you're right. I re-did the calculation again and paid proper attention to parenthesis this time. I'm just not calculator savvy at all.