Acceleration
Like any other force, a body force will cause an object to accelerate. For a non-rigid object, Newton's second law applied to a small volume element is
- ,
where ρ(r) is the mass density of the substance, ƒ the force density, and a(r) all at point r.
In the case of gravity, a(r) is simply the acceleration due to gravity, that is the gravitational field g.
Read more about this topic: Body Force