ch14_nrqd

__Satellite motion__ A period is the time for a satellite to do a complete orbit around the earth. and its about 90 minutes. Knetic energy and potential energy stay constant everywhere during the satellites orbit.

Throw a stone at any speed and one secound later it will have fallen 5m below where it would have been without gravity.

A satellite in circular orbit close to the earth moves tangentally at slums during each secound it falls 5m between each

** in the Solar System **
 * Escape Speeds at the Surface of Bodies **
 * __ASTRONOMICAL BODY MASS RADIUS ESCAPE SPEED__ [[image:http://blog.dotphys.net/wp-content/uploads/2008/08/fixed-orbit.jpg width="286" height="305" align="right"]] **

Circular orbits a circular orbit is the speed of a circling satellite is not changed by gravity. Elliptcal orbits an ellipse is a specific curve the close path taken by a point that moves in such a way that the sum of its distance from two fixed points called foci.
 * SUN || 333000 || 109 || 620 ||
 * SUN at distance of earth orbit || 23 || 500 || 42.2 ||
 * Jupiter || 318 || 11 || 60.0 ||
 * Saturn || 95.2 || 9.2 || 36.0 ||
 * Neptune || 17.3 || 3.47 || 24.9 ||
 * Uranus || 14.5 || 3.7 || 22.3 ||
 * Earth || 1.00 || 1.00 || 11.2 ||
 * Venus || 0.82 || 0.95 || 10.4 ||
 * Mars || 0.11 || 0.53 || 5.0 ||
 * Mercury || 0.055 || 0.38 || 4.3 ||
 * Moon || 0.0123 || 0.27 || 2.4 ||

The first probe to ecsape the solar system pioneer 10 was launched from earth in 1972 with a speed of only 15 km/s.

The potential energy is greatest when the satellite is farlest away at the apogee.