The mass of the planet Earth is 6.0 * 10^24 kg, and its radius is 6.38 * 10^6 m.

(a) A communications satellite orbits at an altitude of 32,000 km (about 20,000
miles) above Earth's surface.  Unexpectedly, it's hit by a piece of space debris.
A chunk of the satellite is knocked loose and falls downward toward Earth.  If
this chunk has a mass of 2 kg, how much gravitational potential energy will
have been released when the brick hits the ground? 

(b) A robotic hypersonic test plane flies altitude of 32 km (about 20 miles)
above Earth's surface.  If a chunk of this airplane with mass 2 kg were 
knocked loose and fell to Earth, how much gravitational potential energy
will have been released when the brick hits the ground?

(c) Use the simplified version of the gravitational potential energy equation
on the cases of both Part (a) and Part (b).  Does the equation work?  Why or
why not?