A space vehicle approaching a planet has a speed

PHYSICS · Single correct · CBSE · Physics · Gravitation · Gravitation

Problem

A space vehicle approaching a planet has a speed vv, very long way out and is on a trajectory which would miss the centre of the planet by a distance RR if it continued in a straight line. If the planet has a mass MM and radius rr, what is the smallest value of RR in order that the resulting orbit will just miss the surface: (1) R=2GMvrR = \frac{2GMv}{r} (2) R=vr[1+2GMr]R = vr \left[ 1 + \frac{2GM}{r} \right] (3) R=rv[v2+2GMr]R = \frac{r}{v} \left[ v^2 + \frac{2GM}{r} \right] (4) R=rv[v2+2GMr]1/2R = \frac{r}{v} \left[ v^2 + \frac{2GM}{r} \right]^{1/2}

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