Hi,

I've attached a diagram of the described situation.

R is the radius pointing to A resp. A'. R = 16"

r is the radius pointing to B. r = 15"

When the wheel performs the angle , the the point A moves back.

You've got right triangles so you can calculate :

. Thus = 40.728°

The perimeter of the (active) wheel =

Now calculate the number of revolutions per second. I've got 8.8837885 rps. (Please check my result carefully. I'm the king of mistakes here!).

That means the wheel performs 8.8837885 * 360° = 3198.16° per second.

The time which is needed to perform the angle :

(By the way: Why do you want a time exact to billionst second?)

EB