Physics

Physics · optics

Problem

Example 3.3. We observed a sinusoidal wave travelling along the

x

-axis at two positions (

x=0

and

x=1 \mathrm{~m}

), and found the displacements of the wave at these two positions as follows:

y(0, t)=0.2 \cos (3 \pi t), \quad y(1, t)=0.2 \cos (3 \pi t+\pi / 8)

Find the frequency, wavelength and speed of propagation of this wave in both cases in which the wave travels in the

+x

and

-x

directions, using the appropriate integer,

n

. Enumerate all the possible values of the wavelength longer than 0.7 m .