Mathematica Representation of a wave

[ku1005]

Homework Statement

"A sinusoidal wave is propagating along a stretched stringas a function of time is graphed in the figure (attached) for particles at x = 0 and x =0.0900m. a) what is the period of the wave ( my ans = 0.04 sec

b) what is the amplitude of the wave ( my ans = 4mm)

c)you are told that the 2 points x=0 and x=0.0900m are within one wavelength of each other. If the wave is moving in the +x direction, determine the wavelenght and the wave speed."

Homework Equations

y(x ,t) = A cos(2pi ( x/lambda - t/T))

ie the mathematical representation of a wave

The Attempt at a Solution

I have already posted this Q previously, but fear that how I posted it made it seem unsolvable, this is what I did again:

0.75 = cos (2pi (0.09/lambda - 0 )) where I get lambda, and thus wavelength to equal 0.78... which isn't correct since the answer is something like 0.14m

any pointers on how to solve would be great!

 

[apelling]

I can't open your attachment as yet (its still pending approval) but I'll assume you took the period and amplitude from information of the graphs.

Do the two graphs should show a phase difference? If they do, you can easily use this to establish how long the wave takes to get from the first point to the second. Youve then got a distance and a time from which a speed is easy.

 

[ku1005]

yeah i got it now...u use the distance travelled...ie between 2 waves...so from say a peak to the next peak ...adn diide by time...makes it REAL simple when you consider this way...cheers for the attempt...no1 else seemed to b able to get it?