Question

Two spherical objects have masses of 1.5 x 105 kg and 8.5 x 102 kg. Their centers are separated by a distance of 2500 m. Find the gravitational attraction between them.

Answer 1

Given:

$m_1=1.5 *10^5\:\rm kg$

$m_2=8.5 *10^2\:\rm kg$

$r=2500\:\rm m$

The law of universal gravitation says

$$F=G\frac{m_1m_2}{r^2}$$ $$F=6.67*10^{-11}\frac{1.5*10^5*8.5*10^2}{2500^2}=1.4*10^{-9}\:\rm N$$