What is the period of oscillation in this graph?

[mikefitz]

What is the period of oscillation in the screenshot?

http://img296.imageshack.us/img296/5296/image12yt4.gif

Period is just the time it takes to travel from one point on the graph to the exact same point again in the same direction. Looking at the graph I would guess somewhere around 2.5 seconds, but every answer I enter in the online submission says incorrect. This should be so simple but I can't figure out why all my answers are wrong?

 

[physics girl phd]

maybe you didn't read the divisions right... or try to look at the time of something like TEN waves, and divide that by ten... I'm guessing that your answer might have too much error to be considered correct.

 

[Max Eilerson]

Take an average over the whole wave. It's pretty clear the period is less than 2 seconds.