A sinusoidal wave is propagating along a stretched string that lies along the x-axis. The displacement of the string as a function of time is graphed in the figure (attachment) for particles at x=0m and x=0.0900m.
(A) What is the amplitude of the wave?
(B) What is the period of the wave?
I am confused by the following questions:
(C) You are told that the two points x=0 an x=0.09m are within one wavelength of each other. If the wave is moving in the +x-direction, determine the wavelength and wave speed.
ANSWER KEY: 0.14m and 3.5m/s
(D) If the wave is moving in the -x-direction, determine the wavelength and wave speed.
ANSWER KEY: 0.24m and 6.0m/s
y(x,t)=Acos(kx +/- ωt)
The Attempt at a Solution
Initially I thought the wavelength would be 0.09 since it says 0 and 0.09 are one wavelength away from each other... But then I looked at the answer key and it seems my interpretation is wrong. Does anyone know what the question is asking in C?