# Help w/ simple dimensional analysis

1. Sep 18, 2009

### CocoonOHorror

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

where F is the magnitude of the gravitational attraction on either body, m_1 and m_2 are the masses of the bodies, r is the distance between them, and G is the gravitational constant. In SI units, the units or force are kg* m/s^2, the units of mass are kg, and the units of distance are m. For this equation to have consistent units, the units of G must be which of the following?

2. Relevant equations

F=GM_1M_2/r^2

3. The attempt at a solution
i have no idea where to begin. it seems to me they should give me the dimensions of mass and force, but they dont.

Last edited: Sep 18, 2009
2. Sep 18, 2009

### physicsface

Plug in the units and solve for the gravitational constant.

3. Sep 19, 2009

### Redbelly98

Staff Emeritus
Actually they do give that information:

4. Sep 19, 2009

### CocoonOHorror

those are the dimensions?

5. Sep 19, 2009

### Redbelly98

Staff Emeritus
Yes.

6. Sep 19, 2009

### CocoonOHorror

man, i reall dont understand the question then :surprised

7. Sep 19, 2009

### Redbelly98

Staff Emeritus
Exactly. Plug in the units for F, M1, M2, and r in the equation,