Two point masses and are placed apart and attract each other with force

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

Problem

Two point masses

m

and

2m

are placed

r

apart and attract each other with force

F

. They are replaced by two new masses

3m

and

4m

placed a distance

x

apart, yet the force remains

F

. What is the ratio

\dfrac{x}{r}

? (a)

\sqrt{3}

(b)

\sqrt{6}

(c)

\dfrac{3}{2}

(d)

\sqrt[3]{6}