A steel ball of mass has diameter and a brass ball of mass has diameter

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

Problem

A steel ball of mass

2\,\text{kg}

has diameter

10\,\text{cm}

and a brass ball of mass

3\,\text{kg}

has diameter

8\,\text{cm}

. They are placed in line with a

4\,\text{cm}

thick non-metallic spacer between their surfaces. Calculate the magnitude of the gravitational force between the two balls. Take

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

. (a)

1.2\times10^{-7}\,\text{N}

(b)

4.0\times10^{-8}\,\text{N}

(c)

2.4\times10^{-8}\,\text{N}

(d)

2.4\times10^{-9}\,\text{N}