Posted by Nina on .
a satellite has a mass of 100 kg and is located at 2 x 10^6 m above the surface if the Earth. wHAT is the potential energy associated with the satellite at this location? What is the magnitude of the gravitational force on the satellite?

physics(universal law of gravitation) 
drwls,
The earth's radius is about Re = 6.4*10^6 m. At 2*10^6 m above the surface, you are R = 8.4*10^6 m from the center of the Earth. The acceleration of gravity is reduced by a ratio
(6.4/8.4)^2 = 0.58
and g is reduced to g'= 5.7 m/s^2
The potential energy (relative to the ground), is M G[1/Re  1/R]. G is the universal constant here.
This P.E. will be somewhat less than
M * g *altitude, because g is not constant with altitude
The gravity force is M g'