# Calculate the gravitational field of a object

1. Jun 1, 2004

### taylordnz

how do you calculate the gravitational feild of a object e.g black hole (does it refer to its density and mass?

2. Jun 2, 2004

### Gza

$$\vec{g} = \frac {GM_1} {r^2} \hat{r}$$

if the source mass has a non spherical distribution and you know its density(or density function) you will have to integrate the above equation replacing m by little dm's. Since you must integrate on a geometry, you have to somehow relate the dms to the geometry of the problem (big hint use density) To justify this action, the principle of superposition applies, since it is the superposition of all the little fields generated by the dm's that are added up in the integral. Sorry this answer is so vague, if you can make your question more specific, I can give you a more specific answer.

Last edited: Jun 5, 2004
3. Jun 2, 2004

### TALewis

Gza, do you intend that $\vec{r}$ is a unit vector of the r direction?