What is the magnitude of the gravitational force that acts on each particle in Figure 4.9, assuming m₁ = 12 kg (approximately the mass of a bicycle), m₂ = 25 kg, and r = 1.2 m?

Reasoning and Solution   The magnitude of the gravitational force can be found using Equation 4.3: For comparison, you exert a force of about 1 N when pushing a doorbell, so that the gravitational force is exceedingly small in circumstances such as those here. This result is due to the fact that G itself is very small. However, if one of the bodies has a large mass, like that of the earth (5.98 × 10²⁴ kg), the gravitational force can be large.