# Attraction and gravitational force.

1. Oct 20, 2007

### fineztpaki

1. The problem statement, all variables and given/known data
Two objects attract each other gravitationally with a force of 2.7 10-10 N when they are 0.25 m apart. Their total mass is 4.0 kg. Find their individual masses.
larger mass - I kind of guessed this was 4.0 kg but don't know how to do it.
smaller mass ? kg

3. The attempt at a solution

I don't quite understand how exactly this must be done. What formulas would i use?

2. Oct 20, 2007

### Staff: Mentor

Use Newton's Law of Gravity. (No guessing allowed!)

Call the masses M1 and M2, if you like.

3. Oct 20, 2007

### fineztpaki

ahh.. i still dont get it???

4. Oct 20, 2007

### Staff: Mentor

5. Oct 21, 2007

### bourne

take two masses M1 and M2. problem says that M1+M2= 4.
Newton's law of gravitation says that force between two objects of mass M1 and M2 is

F = (gravitational constant) x (M1) x (M2) / (square of the distance)

so u know F, gravitational constant, the value of distance. Substitute these values in the above equation, u gonna get a relation beween M1 and M2 something like ,
M1= something times M2

substiute that in M1 + M2 = 4,