Why does a finger in the middle of a spinning fan trace a larger circle?

[unique_pavadrin]

Homework Statement

Hey just a quick question that bothering me:

how come when u stick your finger in the middle of the fan and let it move it goes in a larger circle?

 

[Shooting Star]

Only the centre of the fan is not moving. But that's a one dimensional point. All other points on the fan are moving. The tip of your finger is a 2-d surface. Generally, due to friction, your finger will get shifted ever so slightly from the exact centre, and so you'll see it going around in a circle.

If you press it hard against the centre, you'll see it doesn't move much. But don't try it.

 

[unique_pavadrin]

okay thanks makes sence