physics help

Question

 if a satellite orbits the earth with a  period of 120 minutes, determine its altitude above the earths surface. Show all work and answer to three significant digits please. 

Answer 1

Use Kepler's 3rd law:

 

T² = (4π² / GM) R³

 

T = period = 120*60 s = 7200 s

 

G = universal constant of gravitation (look up)

 

M = mass of earth (look up)

 

R_e = mean radius of earth (look up)

 

h = altitude above surface of earth = ?

 

R = radius of orbit = R_e + h

 

From Kepler's 3rd law,

 

R = (GMT² / 4π²)^1/3

 

Plug in G, M, and T to get R.  Then

 

h = R - R_e

 

Be careful with units.  Can you finish from here?