physics
posted by natash .
why is the total distance traveled by a mass traveling in a circle of radius R during n revolutions =2piRn. The average speed is the distance traveled divided by the elapsed time, so:
v=2piRn/delta T, where delta T is the elapsed time.

in a revolution it travels one circumference 2 pi R. Try it with a coin on your desk to see what is happening.
then speed = distance/time