Question: An astronomer observes a protoplanetary disk rotating uniformly, where a planetesimal orbits along a circular path of radius $ R $. If the arc length between two opposite points on the orbit is $ 120^\circ $ of the circle, what is the ratio of the chord length (distance between these two points) to the radius $ R $?

Mon, 04 May 2026 11:35:49 +0000

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