How to determine the angular acceleration using the right hand rule?

[ehabmozart]

How to determine the angular acceleration using the right hand rule??

I know how to get the direction of angular velocity using RHR. We curl up our fingers to the direction at which the object rotates relative to an aix and the thumb shows the direction. My question is, with the same analogy, how can we determine the angular acceleration using the right hand rule?? Adding to this, what does clockwise or anti cc suggest to the direction of angular vectors? THanks a lot to whoever contributes :)

 

[D'Alembert]

Angular acceleration is $ω^{2}$r. You can represent it also as a cross product: ω$\times$(ω$\times$r)

Now use the Right Hand Rule and you will come to the direction known for the angular acceleration.