Gravitational force of a basketball to a golf ball

[kolua]

Homework Statement

Two basketballs, each of mass 0.58 kg and radius0.12 m, are placed on a floor so that they touch each other. Two golf balls, each of mass 0.045 kg and radius 22 mm, are placed on a table so that they touch each other.
What is the ratio of the gravitational force exerted by one basketball on the other to that exerted by one golf ball on the other?

Homework Equations

F=GMm/r^2

The Attempt at a Solution

F_bb=G m_bxm_b/r1²
F_gg=G m_gxm_g/r2²
[/B]
I got the result of 5.58
is this correct?

 

[PeroK]

Homework Statement

Two basketballs, each of mass 0.58 kg and radius0.12 m, are placed on a floor so that they touch each other. Two golf balls, each of mass 0.045 kg and radius 22 mm, are placed on a table so that they touch each other.
What is the ratio of the gravitational force exerted by one basketball on the other to that exerted by one golf ball on the other?

Homework Equations

F=GMm/r^2

The Attempt at a Solution

F_bb=G m_bxm_b/r1²
F_gg=G m_gxm_g/r2²
[/B]
I got the result of 5.58
is this correct?

That's a weird question. It's also a poor question, as you can get the right answer by taking $r_b = 0.12m$ and $r_g = 0.022m$. Is that what you did?

 

[kolua]

That's a weird question. It's also a poor question, as you can get the right answer by taking $r_b = 0.12m$ and $r_g = 0.022m$. Is that what you did?

Yes and I got the ratio of 2757 not 5 sorry. is that correct?

 

[PeroK]

Yes and I got the ratio of 2757 not 5 sorry. is that correct?

Have a think about what $r$ should be when you have two objects of a given radius.

Your original answer was correct, by the way.

 

[kolua]

Have a think about what $r$ should be when you have two objects of a given radius.

Your original answer was correct, by the way.

Got it! I put the wrong number in calculator. THX!