Two planets, A and B

PHYSICS · Multi-part · CBSE · Physics · Gravitation · Gravitation

Problem

Two planets, A and B, form a binary system in otherwise empty space. Planet A has mass 6.0×1024 kg6.0\times10^{24}\,\text{kg}. The center-to-center separation of the planets is 3.8×108 m3.8\times10^{8}\,\text{m}. Along the line joining their centers is a point PP where a small test mass would experience zero net gravitational field. Point PP is located 1.5×108 m1.5\times10^{8}\,\text{m} from the center of Planet A. Use G=6.67×10−11 N ⁣⋅ ⁣m2/kg2G=6.67\times10^{-11}\,\text{N}\!\cdot\!\text{m}^2/\text{kg}^2. (a) Derive an equation that relates the masses of Planets A and B to the given distances at point PP where the net gravitational field is zero. (b) Determine the mass of Planet B. (c) A 1200 kg1200\,\text{kg} spacecraft is placed exactly at point PP and then is given a slight nudge toward Planet A. Describe qualitatively the subsequent motion of the spacecraft and explain your reasoning in terms of the gravitational forces acting on it.

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