# Homework Help: Universal law of gravity

1. Oct 4, 2007

### Rgonzales

1. The problem statement, all variables and given/known data

Two tankers of equal mass attract eachother with a force of 3.5 x 10(to the power of 3)N. If their centres are 85m apart, what is the mass of each tanker?

mass of 2 tankers = ?
F= 3.5 x 10(to the power of 3)N
r= 85m
G = 6.67 x 10(to the power of -11) N.m(squared)/kg(squared)

2. Relevant equations

F = G x m1 x m2
r(squared)

3. The attempt at a solution

Last edited: Oct 4, 2007
2. Oct 4, 2007

### D H

Staff Emeritus
Given this:

why do you have two separate masses, m1 and m2?

3. Oct 4, 2007

### Avodyne

What does that tell you about m1 and m2?

4. Oct 4, 2007

### Rgonzales

yeah i just noticed awhile ago...so do i just sub them all the info and isolate the variable of the tank?

Last edited: Oct 4, 2007
5. Mar 7, 2011

### ogaitnas312

step 1 since the two mases are the same you can express it as m(^2)
step 2 rearrange the formula to get m(^2) =3.5x10(^3) x 85(^2)/6.67x10(^-11)
step 3 square root the final answer to get the mass of the tanker and you should get 6.16x10(^8)N