Why Is the Lag Time 60 Degrees Instead of 72 Degrees in Wave Phase Calculations?

[ishterz]

Hi,

I came across this question on waves which tells you how to calculate the phase difference and the lag time but I don' uderstand why it is 60 degrees.Although I'm notable to draw th diagram,I will write down the explanation

What is the phase relationship b/w the two signals?(y1 and y2)

The difference between the squares of the signals on the graphs is 4 and one wavelength of y2 is 20 squares.
So it says that the lag is 1/5 of a cycle of 360 degrees which is 60 degrees.

I understand where the 1/5th came from but how is it 60 and not 72 which is what you get after you divide 5 by 360? I thought the answer was wrong but similar questions have answers mismatched with mine as well.

So please help! I've got my exam tomorrow!

Thanks

 

[cartonn30gel]

According to your description, I can't find any flaws in your solution. Especially if it says "the lag is 1/5 of a cycle of 360 degrees which is 60 degrees", there is probably a small math error. I can't be sure without the diagram though.

Can you try to post a picture?

 

[ishterz]

I tried posting the picture up but it was unsuccessful. I've pretty much described it in the question though.
I don't understand,how is 60 1/5 of 360? isn't it 1/6th ? Why is it saying 1/5th ? =S

 

[cartonn30gel]

They probably just made a small mistake. Try some other examples and the concepts will become clearer. Don't get hung up on the same problem.