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# Geostationary Orbits- Old exam question

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1. Hey guys, my teacher's set this booklet based on some really old exam questions; it's based on gravitational fields and obviously geostationary orbits;

In part II) it asks you to calculate the height of the satellite above the earth, as it's a geostationary orbit, would it not be 35,000~ KM? I can't seem to figure out where I'm wrong, I've rearranged:

T^2= (4PI^2/GM)*r^3

For the radial distance, subtracted earth's radius from the radius of the satellite from the center, and my answer is hugely out from the actual value of a geostationary orbit, any help would be much appreciated and part III is a complete shambles at the moment too, picture attached below. (Sorry for the quality!)

Cheers guys!
Attached Images

2. method looks legit (afaict from that photo ) , are you sure you keyed it correctly into your calc?

I get 4.22x10^7 m radius above CoM (3.59x10^7 m above surface)
3. Rearrange
T^2= (4PI^2/GM)*r^3

To give a value for r.

We know the values if Pi, G, M, 4, and T.

Substitute a value of (24 x 60 x 60) for T

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