Radians
posted by Jessica on .
The angular speed of a large pulley wheel that has a radius of 15, is 50 revolutions/min. Find the angular speed and the rim speed of the smaller wheel that has a radius of 5.
The rim speed is going to be the same.
I got the angular speed but I can't figure out why the rim speed is 4700 cm/min.
Please Help

rim speed=angular speed*radius
rim speed=50rev/min*2PIrad/1rev*15cm
= 4700cm/min 
where did you get the 2Plrad?