posted by anonymous .
1. Calculate the speed in m/s at which the Earth revolves about the sun. You may assume the orbit is nearly circular.
2. A satellite is about 6.5 x 10^3 km from the (center of the) Earth. Find its average orbital speed about the Earth.
3a. A certain satellite has a kinetic energy of 8 billion joules at perigee (closest to Earth) and 7 billion joules at apogee (farthest from Earth). As the satellite travels from apogee to perigee, how much work does the gravitational force do on it?
3b. Does its potential energy increase or decrease during this time, and by how much? (Enter a positive answer if the energy increases, and a negative answer if the energy decreases.)
2.96 x 10^4 m/s