Issy14 one year ago Please explain and guide,, DON'T tell me the answer. A bowling ball (mass ball (mass 0.38 kg, radius 7.2 kg, radius 0.11 m) and a billiard 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? I'm looking for someone to guide me to the answer not to tell me the answer. This is what I know and have: Fg = G Mm/r^2. G= 6.674x10^-11. My question is how to find the distance?

1. AndreyZn

I think I can help you, but sorry for my english! You have right formula of gravitational force and you can see that G, M and m are constants, but r you can change. And if r smaller than F bigger. Let's make r=0, you can say. Can we? To answer this question we have to understand What is the r distance between? The law of universal gravitation states that Fg = G Mm/r^2 for two point mass. Point! It's important! But our bowling ball and billiard ball are not points. But we can mentally break our balls to manymany pieces and calculate force for each piece than summ this forses. Matematicians create special theory and they can immediately say this summ! I'm not going to tell about this theory I will say only the result - the result force will be as If all of ball's mass would be concentrate in the centers of balls. So, we take our balls, press them to each other (as r - minimum) and calculate force as if all balls would be points, that is r=r1+r2, where r1-radius of bowling ball and r2-radius of billiard ball. P.S. we can't make r=0 because r is the distance between centers of two balls. Ask if something is not clear

2. Issy14

Thank you!!! You English is just fine!! =)