plz help me wid d numerical

Asked by  | 9th Jan, 2009, 08:45: PM

Expert Answer:

  1. The force of gravity does no work on a satellite in circular orbit since the force is always perpendicular to the planet's direction of motion.The gravitational force does do work on a satellite in elliptical orbit because there is a component of the force in the direction the satellite moves.
  2. Note that as the satellite is moving away from the Sun, the gravitational force is doing negative work on the satellite, so GPE is being stored (KE converting to GPE). As the satellite moves toward the Sun, the gravitational force does positive work, and the satellite speeds up (GPE converting to KE). The total work done by gravity in a complete orbit is zero.
  3. The gravitational force doesn't change the speed of a satellite in circular orbit because the force is always perpendicular to the direction of motion of the satellite. Therefore, the force changes the direction of the satellite, but not its speed.

Answered by  | 10th Jan, 2009, 11:45: AM

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