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# Dynamics and Relativity

1. 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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2. 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.
3. Right, I was wondering that, just it seems pretty simple. Its a 3 mark question, which would be quite generous
4. (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?
5. 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).
6. oh yeah of course, cheers

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