physics
posted by Anonymous on .
A toy train is on a track which has a circumference of 10 meters. The train takes 20 seconds to complete one revolution around the
track.

You posted this question twice.
They tell you how far it travels in 20 seconds. Divide the circumference by that time to get the speed.
The average velocity will depend upon the time interval of the measurement. For any multiple of 20 seconds, you end up on the same place. That should be a clue.