postion, velocity and aceleration ...

[Osvaldo Fornaro]

Hi,

I need to write r , r dot (r with a dot above it) and r dot dot (r with
a double dot above it) representing a first and a second derivate of a
vector in math mode.

How is it possible to obtain this?

Thanks in advance,

Osvaldo Fornaro
Univ. Nac. del Centro
Argentina