How Far is the Satellite from Earth?

[Feodalherren]

Homework Statement

A 320kg satellite experiences a gravitational force 800N. What is the radius of the satellite's orbit?

Homework Equations

G m1m2 / d^2

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?

 

[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?

 

[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.

 

[Feodalherren]

Shameless bump. Still need help.

 

[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.

 

[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.