How to know if a force is body force or not?

[arbit_daaku]

If, in a problem, I want to know if a given force is body force or not, what should I do? for example- a rod rotating about an axis, how will I know if the centripetal force is Body Force or not?
(body forces are those forces which depend on volume)

 

[jedishrfu]

check this wiki article and see if it answers your question:

http://en.wikipedia.org/wiki/Body_force