13. A geostationary satellite for communications seems to be in a
fixed spot above the equator because it has the same angular
velocity as the earth.
a) Show that if it goes round once a day, its angular velocity
w is a little over 7 x 10-5 rad/s.
b)
Geostationary satellites are placed in orbits of radius
4.2 x 104 m. Use this information to deduce g, the
acceleration of a freely falling body, at this height.