Two point masses and are fixed apart

PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

Two point masses

6\,\text{kg}

and

24\,\text{kg}

are fixed

12\,\text{m}

apart. Take

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

. What is the gravitational potential per unit mass at the null point between them? (a)

+3.0\times10^{-10}\,\text{J kg}^{-1}

(b)

-3.0\times10^{-10}\,\text{J kg}^{-1}

(c)

-4.5\times10^{-10}\,\text{J kg}^{-1}

(d)

-2.0\times10^{-10}\,\text{J kg}^{-1}