Homework Help: 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,