Angular velocity: prayer wheels at Samye Ling

We visited the Samye Ling Buddhist monastery at Eskdalemuir in southern Scotland. They have a building full of electrically turned prayer wheels. I forgot to time the rotation but it was about 20 seconds. Angular velocity is not the metres covered per second, but the number of degrees. And actually, we don't use degrees, we use another measure of angle called RADIANS. There are 2pi radians for every 360 degrees - that's about 6.28 radians. So a complete circle in 20 seconds would mean an angular velocity of 6.28/20 = 0.314 radians per second.