Question

Two spherical objects have masses of 66g and 35 g. The gravitational attraction between them is 6.5 x 10-3 N. How far apart are their centers?

Answer 1

Given:

$m_1=0.066\:\rm kg$

$m_2=0.035\:\rm kg$

$F=6.5*10^{-3}\:\rm N$

The Newton's law of universal gravitation says

$$F=G\frac{m_1m_2}{r^2}$$

Hence, the distance between bodies

$$r=\sqrt{G\frac{m_1m_2}{F}}$$

$$r=\sqrt{6.67*10^{-11}\frac{0.066*0.035}{6.5*10^{-3}}}=4.9*10^{-6}\rm\: m$$