Three Chapter 2

Escape From The Earth's Gravitational Field

• If velocity of the object is less than the escape velocity, then the total energy is less than zero and escape is impossible
  • i.e. if not put in orbit, the object will fall back to the planet.
• Binding Energy - The amount of additional kinetic energy an object needs to escape a planet. This is the amount of energy represented by B on the above graph.
• For a bound satellite in orbit of radius r_o we have

• This satellite will experience a centripetal force provided by the gravitational force on it.

• To cause this bound satellite to escape, we have to add kinetic energy so that the total energy is greater than or equal to zero. This added kinetic energy is binding energy (E_B).

• Three possible cases exist

December 13, 2013