# Problem 1-20| General Principles| Engineering Mechanics: Statics| RC Hibbeler

#### Two particles have a mass of 8 kg and 12 kg, respectively. If they are 800 mm apart, determine the force of gravity acting between them. Compare this result with the weight of each particle.

Solution:

The force of gravity acting between them:

$F=G\cdot \frac{m_1m_2}{r^2}=66.73\left(10^{-12}\right)\left[\frac{8\left(12\right)}{0.8^2}\right]=10\left(10^{-9}\right)N=10.0nN$

Weight of the 8 kg particle

$W_1=8\left(9.81\right)=78.5\:N$

Weight of the 12 kg particle

$W_2=12\left(9.81\right)=118\:N$