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-   -   Elliptical motion of satellite around planet (https://www.askmehelpdesk.com/showthread.php?t=314969)

  • Feb 8, 2009, 08:54 PM
    aanuteju
    Elliptical motion of satellite around planet
    Why a satellite have greater speed when its radius of rotation is less ? By energy arguments please explain this.
  • Feb 8, 2009, 08:56 PM
    aanuteju

    Why a satellite has greater speed in elliptical orbit when its radius of rotation is less around a planet ?
  • Feb 8, 2009, 08:58 PM
    aanuteju
    Why a satellite have greater speed when its radius of rotation is less ? By energy arguments please explain this.
  • Feb 9, 2009, 01:13 PM
    ebaines

    Here's a hint - think about what happens to a satellite's potential energy as the distance to the planet it orbits decreases - as it gets lower in the gravitational field its PE decreases, right? So what does that mean would happen to its kinetic energy?
  • Feb 9, 2009, 05:34 PM
    sarnian
    At any moment during the orbit the total amount of energy is the same.

    Lets consider a bullet fired upwards. First it has kinetic energy from it's speed. While climbing that energy is converted into potential energy. When the kinetic energy is nill, the potential energy is maximal. Now the bullet starts falling down again, and potential energy is converted into kinetic energy, while it's speed picks up again.

    Now imagine that the bullet goes extremely fast, so fast that it gets into an eliptic orbit around earth. At the 'highest' point the speed away from earth is nill. But nearest to earth it's speed is maximum.
  • Feb 18, 2009, 12:53 AM
    visharad

    When the satellite is closer to the Earth, then it has smaller gravitational potential energy. Hence, larger kinetic energy and thereby larger speed.

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