A bowling ball (mass = 7.2 kg, radius = 0.14 m) and a billiard ball (mass = 0.40 kg, radius = 0.028 m) may each be treated as uniform spheres. What is the magnitude of the maximum gravitational force that each can exert on the other?

Answer 1

since the minimum distance between their centers of mass is .14m + .028m = .168m,
plug that into the usual formula.

BTW, who ever heard of a 2.8cm, 400g billiard ball? The standard size and weight are around 5.7cm and 160g.

Maybe a golf ball is 2.8cm. Dunno.