Question

Difficulty: HardWave Properties and Mathematical Wave Equation

A progressive transverse wave traveling along a taut string is governed by the displacement equation y(x,t)=0.05sin(200πt10πx)y(x,t) = 0.05 \sin(200\pi t - 10\pi x), where xx and yy are measured in meters and tt in seconds. Calculate the distance, in meters, traveled by the wave front during the time taken for a single particle on the string to complete 1515 full oscillations.

Answer: 3 m

Answer

The distance traveled by the wave front during 15 full particle oscillations is 3.0 m3.0\text{ m}.
Comparing y(x,t)=0.05sin(200πt10πx)y(x,t) = 0.05 \sin(200\pi t - 10\pi x) to the standard wave equation y=Asin(ωtkx)y = A \sin(\omega t - kx) gives ω=200π rad/s\omega = 200\pi\text{ rad/s} and k=10π rad/mk = 10\pi\text{ rad/m}. The wave speed v=ωk=20 m/sv = \frac{\omega}{k} = 20\text{ m/s}. The time for one full oscillation is T=2πω=0.01 sT = \frac{2\pi}{\omega} = 0.01\text{ s}, so 15 full oscillations take t=15×0.01 s=0.15 st = 15 \times 0.01\text{ s} = 0.15\text{ s}. The distance traveled by the wave front is d=v×t=20 m/s×0.15 s=3.0 md = v \times t = 20\text{ m/s} \times 0.15\text{ s} = 3.0\text{ m}. Alternatively, because a wave travels a distance of one wavelength λ=2πk=0.2 m\lambda = \frac{2\pi}{k} = 0.2\text{ m} during each period (1 full oscillation), in 15 full oscillations the wave travels 15×λ=15×0.2 m=3.0 m15 \times \lambda = 15 \times 0.2\text{ m} = 3.0\text{ m}.

Step-by-Step Solution

1
Extract wave parameters from the progressive wave equation
Angular frequency ω=200π rad/s\omega = 200\pi\text{ rad/s} and wave number k=10π rad/mk = 10\pi\text{ rad/m}.
Matching the given equation y=0.05sin(200πt10πx)y = 0.05 \sin(200\pi t - 10\pi x) with the standard form y=Asin(ωtkx)y = A \sin(\omega t - kx) identifies ω\omega and kk.
2
Calculate the wave propagation velocity
v=20 m/sv = 20\text{ m/s}.
Wave speed is given by the relation v=ωk=200π10π=20 m/sv = \frac{\omega}{k} = \frac{200\pi}{10\pi} = 20\text{ m/s}.
3
Find the period of oscillation and total elapsed time
Period T=0.01 sT = 0.01\text{ s}, total time t=0.15 st = 0.15\text{ s}.
The period T=2πω=2π200π=0.01 sT = \frac{2\pi}{\omega} = \frac{2\pi}{200\pi} = 0.01\text{ s}. For 15 complete oscillations, t=15×0.01 s=0.15 st = 15 \times 0.01\text{ s} = 0.15\text{ s}.
4
Compute the total distance traveled by the wave
Distance d=3.0 md = 3.0\text{ m}.
Using linear motion at constant wave speed, d=v×t=20 m/s×0.15 s=3.0 md = v \times t = 20\text{ m/s} \times 0.15\text{ s} = 3.0\text{ m}.

Key Concept

Wave equation parameters, particle oscillation period, and wave propagation distance
Estimated Time:2m 0s
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