試題詳解

10. A planet of mass m orbits the sun of mass M in an elliptical path (see Figure 1), with the sun at a focal point. In accord with Kepler's laws, a line drawn from the sun to a planet sweeps out equal areas in cqual times, i.e., dAidt is a constant. Assume that the angular momentum of the planet relative to the sun is L, then dA/ dt is given by 

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