# Radial Acceleration in cylindrical coordinates

1. Apr 4, 2008

### VooDoo

Hey guys,

Been given this formula for radial acceleration, im not sure how they derived it. I have tried but the only forumla I know is a(radial) = v^2/r

$$A_{r}$$ = $$\ddot{r}$$ - r$$\dot{\theta}^{2}$$

EDIT - should be minus not plus

Last edited: Apr 4, 2008
2. Apr 5, 2008

### tiny-tim

Hi VooDoo!

They differentiated r.(cosθ.x + sinθ.y), twice!