Physics 581 Homework #4
Due Wednesday 4:30 p.m.
1. Read the notes "More on Potential Energy".
(a) Find the escape velocity from the earth.
(b) Find the escape velocity from the moon.
(c) How does the amount of energy needed to escape from earth compare with the amount of energy needed to put the same mass in low earth orbit?
2. The satellites used for TV signals are mostly in "stationary" orbits, they stay above the same spot on the earth’s surface.
(a) Why is this a good idea?
(b) Could one be put stationary directly above Charlottesville? Explain.
(c) How far are they from the earth’s surface?
3. Read the notes "Spreadsheet Treatment of Simple Pendulum", construct the spreadsheet, and do the three exercises at the end.