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Dynamics and Relativity

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    Problem is on attatchment.
    To solve, I tried to consider the path taken as a section of the circumference, but no use. I'm guessing its to do with the photon detection, but I cant work it out.

    Any help?
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    Two objects in the same orbit around a planet always have the same speed, right?

    At the same altitude, their centripetal accelerations due to gravity are the same. Relations like v=√(ar) show that this implies their speeds are the same.
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    Right, I was wondering that, just it seems pretty simple. Its a 3 mark question, which would be quite generous
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    (Original post by Xdaamno)
    Two objects in the same orbit around a planet always have the same speed, right?

    At the same altitude, their centripetal accelerations due to gravity are the same. Relations like v=√(ar) show that this implies their speeds are the same.
    It dosent say they have the same mass, so the centripetal force isnt neccesarily the same surely?
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    Both the gravitational force of attraction and the required centripetal force are proportional to the mass of the orbiting object, therefore it's speed is independent of mass (in a similar way to the fact that the acceleration of free fall for all objects on earth is the same when you neglect air resistance).
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    oh yeah of course, cheers

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Updated: April 15, 2012
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