Question

Difficulty: MediumWave Properties and Mathematical Wave Equation

A transverse progressive wave traveling along a stretched string is represented by the mathematical wave equation y=0.05sin(160πt8πx)y = 0.05 \sin(160\pi t - 8\pi x), where xx and yy are measured in meters and tt is in seconds. What is the speed of propagation of the wave in m/s\text{m/s}?

Answer: 20 m/s

Answer

The speed of propagation of the wave is 20 m/s20\text{ m/s}.
Comparing the given equation y=0.05sin(160πt8πx)y = 0.05 \sin(160\pi t - 8\pi x) with the standard wave equation y=Asin(ωtkx)y = A \sin(\omega t - kx) gives the angular frequency ω=160π rad/s\omega = 160\pi\text{ rad/s} and wave number k=8π rad/mk = 8\pi\text{ rad/m}. Substituting these into v=ωkv = \frac{\omega}{k} yields v=160π8π=20 m/sv = \frac{160\pi}{8\pi} = 20\text{ m/s}.

Step-by-Step Solution

1
Compare the given wave equation with the standard progressive wave equation.
The standard form is y=Asin(ωtkx)y = A \sin(\omega t - kx). Comparing parameters yields ω=160π rad/s\omega = 160\pi\text{ rad/s} and k=8π rad/mk = 8\pi\text{ rad/m}.
Matching coefficients allows direct extraction of angular frequency and wave number.
2
Calculate the wave speed using the relation between angular frequency and wave number.
v=ωk=160π rad/s8π rad/m=20 m/sv = \frac{\omega}{k} = \frac{160\pi\text{ rad/s}}{8\pi\text{ rad/m}} = 20\text{ m/s}.
Wave speed is defined as the ratio of angular frequency to wave number (v=λf=ωkv = \lambda f = \frac{\omega}{k}).

Key Concept

Wave Equation Parameter Extraction and Wave Speed Calculation
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