Question

Difficulty: EasyWave Properties and Mathematical Wave Equation

A progressive wave traveling along a medium is described by the equation y=0.05sin(20πt4πx)y = 0.05 \sin(20\pi t - 4\pi x), where xx and yy are measured in meters and tt is in seconds. What is the speed of the wave in m/s\text{m/s}?

Answer: 5 m/s

Answer

The speed of the wave is 5.0 m/s5.0\text{ m/s}.
Comparing y=0.05sin(20πt4πx)y = 0.05 \sin(20\pi t - 4\pi x) to the standard wave equation y=Asin(ωtkx)y = A \sin(\omega t - kx), we find ω=20π rad/s\omega = 20\pi\text{ rad/s} and k=4π rad/mk = 4\pi\text{ rad/m}. The wave speed vv is calculated as v=ωk=20π4π=5.0 m/sv = \frac{\omega}{k} = \frac{20\pi}{4\pi} = 5.0\text{ m/s}.

Step-by-Step Solution

1
Identify the wave parameters from the standard equation form
ω=20π rad/s\omega = 20\pi\text{ rad/s} and k=4π rad/mk = 4\pi\text{ rad/m}
Matching the given equation y=0.05sin(20πt4πx)y = 0.05 \sin(20\pi t - 4\pi x) to y=Asin(ωtkx)y = A \sin(\omega t - kx) gives the values for angular frequency ω\omega and wave number kk.
2
Compute wave speed using the relationship v=ωkv = \frac{\omega}{k}
v=20π4π=5.0 m/sv = \frac{20\pi}{4\pi} = 5.0\text{ m/s}
Wave speed is defined as the ratio of angular frequency to wave number.

Key Concept

Wave Speed from Wave Equation
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