orbital motion, natural and artificial satellites

• What does gravity provide?

  The centripetal force that allows planets and satellites to maintain their circular orbits
• Give two examples of artificial satellites

  
  

  1. TV satellites
  2. Satellites used for satellite imaging
• Explain why the radius of a stable orbit must change if the speed changes

  At higher speeds, the object needs a greater centripetal force meaning the gravitational force must increase. This is achieved by the radius of the orbit being reduced
• Why can the force of gravity acting on a satellite affect its velocity?

  The force can alter its velocity since the direction is continually changing
• Can the force of gravity acting on a satellite affect its speed?

  It can't cause a change of speed as there is no force component in the direction of motion
• Explain why the velocity of the satellite changes as it orbits the Earth.

  gravity causes the satellite to accelerate. the acceleration causes a change in direction and the velocity changes because direction changes