Chapter 16: Waves I Flashcards
Mechanical waves can be described as…
Extended disturbances of a medium that contain energy.
What are traveling waves?
Waves in which the energy associated with the wave propagates through the medium.
What are transverse traveling waves?
Waves in which the disturbance of the medium is perpendicular to the direction the wave travels.
What are longitudinal traveling waves?
Waves in which the disturbance of the medium is parallel to the direction the wave travels.
What are standing waves?
Waves in which the energy associated with the wave does not propagate through the medium.
Sinusoidal transverse traveling waves occur on a string when…
One end of the string moves in the y direction with simple harmonic motion.
What wave function describes a transverse sinusoidal traveling wave?
y(x,t) = y(subm)sin(kx - ωt + ϕ)
Transverse sinusoidal traveling waves travel in the ___ direction, while the medium itself oscillates parallel to the ___ direction.
x; y.
What is amplitude (y(subm))?
The maximum displacement from equilibrium.
SI unit: m
Angular frequency, ω, equals ___ and has SI unit ___.
2πf, 2π/T, or kv; rad/s.
Angular wave number, k, equals ___ and has SI unit ___.
w/v, 2π/λ; rad/m.
What is wavelength, λ?
The shortest repeat distance of the wave. λ = 2π/k.
SI unit: m
What is the SI unit of phase angle, ϕ?
radians.
In a uniform string under tension carrying a transverse sinusoidal traveling wave, v (is)/(is not) constant everywhere along the wave. The vector points (towards)/(away from) the direction the wave travels.
Is; towards.
Each small segment of a string carrying a transverse sinusoidal traveling wave moves (parallel)/(perpendicular) to v. The speed of each segment (is)/(is not) constant.
Perpendicular; is not.
What is transverse velocity?
The velocity of the medium as it travels perpendicular to the wave’s velocity.
How do you calculate transverse velocity?
You take the partial derivative of y(x,t), treating x as a constant.
The frequency of the wave’s determines the ___ of the resulting wave.
Frequency.
The speed of a wave is determined by the ___ of the medium.
Properties.
For a wave on a taut string, the speed is determined by…
the square root of tension over the linear mass density of the string (μ).
The average power of a traveling wave is…
p(subavg) = 0.5μv(ω^2)(y(subm)^2)
What is the law of superposition?
The law that states the net wave observed on a string to be the algebraic sum of the two individual waves.
The sum of two waves traveling in the same direction is a sinusoidal (traveling)/(standing) wave with (the same)/(a different) angular frequency as/than the originals.
Traveling; the same.
What is fully constructive interference?
Interference in which the phase difference Δϕ = 0 (meaning they are perfectly in phase), and the highest possible amplitude is achieved.
What is fully destructive interference?
Interference in which the two waves are perfectly out of phase, and the amplitude is equal to zero.
When two identical sinusoidal waves travel on the same medium in opposite directions, they create a…
Standing wave.
In an equation of the form y(x,t), the amplitude is ALWAYS…
Whatever is outside of and multiplied against the sine in the equation.
The maximum amplitude of a standing wave is called a(n) ___, and occurs at kx(suban) = ___.
Antinode; π/2, 3π/2, 5π/2…
The minimum amplitude of a standing wave is called a(n) ___, and occurs at kx(n) = ___.
Node; π, 2π, 3π…
Describe the n-th harmonic.
λ = 2L/n
f(subn) = v/(λ(subn)) = n(v/2L) = nf(sub1)
