# Starting and stopping a heavy rotating disc

I am currently working at a project involving a heavy disc rotating around its center. The disc weights around 2 kg and has a radius of 0,25 m. At every angle π/6, there exists smaller discs of masses from range 0,1 kg to 1 kg 0,15 m from the center. The radius for these are 0,05 m. A picture to illustrate:

I have roughly calculated the moment of inertia when all smaller discs weight 1 kg. Using the formula for a circular plate and Steiner's theorem, the result is:

$$Inertia = \frac{0,25^2}{2} + 12(\frac{0,05^2}{4} + 0,15^2) = 0,34 kgm^2$$

Now I want the disc to be able to spin and stop at these specific angles. Say for instance I want the disc to rotate from 0 to π. This means I need a precise way to control my disc. My plan is to use a servo and some gears to drive this. I need the disc to turn 180° in at least 3 seconds (preferably less). With this angular velocity and inertia, I have realized it might not be the easiest thing to stop this spinning wheel, let alone accelerate it. Here is another image:

The motor does not need to be positioned like that, it would also be possible to drive the disc by positioning the motor on the edge of the disc for example.

What kind of motor should I be looking for, how would I handle stopping the disc? I am looking for general tips on how to accomplish this.