Surface Gravity and Escape Velocity
•Surface Gravity
–The acceleration due to gravity experienced on the surface of a planet.  It can be found using Newton’s Law of Gravitation and F=ma.  For the Earth, it is g = MEarthG/REarth2 and is 9.8 m/s2.
•Escape Velocity is the velocity needed to overcome the surface gravity and escape from a planet.  For Earth it is about 11 km/s.
v_e = \sqrt{\frac{2GM}{r}} = \sqrt{\frac{2\mu}{r}}