4. Newton’s law of universal gravitation is represented by `F = (GMm)/ (r^2)` where `F` is the magnitude of the gravitational force exerted by one small object on another, `M` and `m` are the masses of the objects, and `r` is a distance. Force has the SI units `kg\cdotm//s^2`. What are the SI units of the proportionality constant G?
`G = m^3 / (kg • s^2)`
`F = (GMm)/ (r^2)` `G = (Fr^2)/(Mm)` `G = ((kg•m/s^2)(m^2)) /(kg•kg) ` `G = (kg•m•m^2)/(kg•kg•s^2)` `G = (m^3)/(kg•s^2)`