Two spheres of masses and are initially apart (centre to centre) in deep space

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

Problem

Two spheres of masses

5.0\times10^{6}\,\text{kg}

and

2.0\times10^{6}\,\text{kg}

are initially

4.0\,\text{m}

apart (centre to centre) in deep space. They are slowly brought to a separation of

2.0\,\text{m}

. How much work must an external agent do during this process? (Take

G = 6.67\times10^{-11}\,\text{N m}^{2}\text{kg}^{-2}

.) (a)

1.7\times10^{2}\,\text{J}

(b)

-1.7\times10^{2}\,\text{J}

(c)

8.3\times10^{1}\,\text{J}

(d)

-3.3\times10^{2}\,\text{J}