**Problem : **
What is the gravitational potential energy of the moon with respect to the
earth? The mass of the moon is 7.35×10^{22} kilograms and the mass of
the earth is 5.98×10^{24} kilograms. The earth moon distance is 384
400 kilometers.

**Problem : **
What is the gravitational potential with respect to the sun at the position
of the earth? The mass of the sun is 1.99×10^{30} kilograms and the
mass of the earth is 5.98×10^{24} kilograms. The mean earth-sun
distance is 150×10^{6} kilometers.

**Problem : **
What is the total energy of a 90 kilogram satellite with a perigee distance 595
kilometers and apogee distance 752 kilometers, above the surface of the earth?
The mass of the earth is 5.98×10^{24} kilograms and its radius is 6.38×10^{6} m.

**Problem : **
Calculate the orbital energy and orbital speed of a rocket of mass 4.0×10^{3} kilograms and radius 7.6×10^{3} kilometers above the center of the
earth. Assume the orbit is circular. (*M*_{e} = 5.98×10^{24} kilograms).

**Problem : **
A satellite of mass 1000 kilograms is launched with a speed of 10 km/sec. It
settles into a circular orbit of radius 8.68×10^{3} km above the center
of the earth. What is its speed in this orbit? (*M*_{e} = 5.98×10^{24} and
*r*_{e} = 6.38×10^{6} m).

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