Two point masses and are fixed apart on a straight line

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

Problem

Two point masses

m_1 = 1\,\text{kg}

and

m_2 = 4\,\text{kg}

are fixed

30\,\text{cm}

apart on a straight line. At what distance from the

1\,\text{kg}

mass, along the line joining them, is the net gravitational field intensity zero? (a)

15\,\text{cm}

(b)

10\,\text{cm}

(c)

6\,\text{cm}

(d)

20\,\text{cm}