A planet's orbit around the sun is an ellipse. Consider points A and B on the ellipse. How does the centripetal force exerted on the planet at point A compare to the centripetal force exerted on the planet at point B? How about the potential energies at A and B? Kinetic energies? How about angular momenta?

Estimate the force that the Moon exerts on you when it is directly overhead.

(You need some data from the book to answer this question.)

Two different planets are orbiting the same sun along two different orbits. The red orbit is circular, the blue orbit is elliptical. Compare the speeds of the planet in the blue orbit at points A, B, and E. Compare the speeds of the planet in the red orbit at points C, D and E. The planet in the blue orbit is to be shifted to the red orbit as it passes point E. Does it have to speed up or slow down?

State your reasons for all of your answers.

The space shuttle has to take a spy satellite to a spot 1200 meters above the Earth's surface and release it into a geosynchronous orbit.

Is this possible? If yes, how fast must the satellite be moving when it is released?