The speed of a travelling wave is determined by tracking a point of constant phase. For the wave y = a sin(kx − ωt), the condition 'constant phase' means:
A.
kx − ωt = constant, so that differentiating with respect to time gives k(dx/dt) = ω, hence wave speed v = dx/dt = ω/k
B.
y = constant, so the particle velocity equals wave speed
A. Halves (λ = v/ν → if ν doubles, λ = v/(2ν) = λ_original/2)
5.
The speed of a mechanical wave is determined by:
A.
The frequency of the source generating the wave
B.
The wavelength of the wave
C.
The elastic and inertial properties of the medium (e.g., tension and linear mass density for a string), NOT by the wave's amplitude, frequency or wavelength
D.
The amplitude of the wave — larger amplitudes travel faster
C. The elastic and inertial properties of the medium (e.g., tension and linear mass density for a string), NOT by the wave's amplitude, frequency or wavelength
6.
The formula for the speed of transverse waves on a stretched string with tension T and linear mass density μ is derived using dimensional analysis. The dimensions of T/μ are:
A.
[T/μ] = [MLT⁻²]/[ML⁻¹] = [L²T⁻²], so √(T/μ) has dimensions [LT⁻¹] = m/s ✓
B.
[T/μ] = [M²L⁻¹T⁻²], so √(T/μ) has dimensions [MLT⁻¹]
C.
[T/μ] = [L²T⁻¹], so √(T/μ) has dimensions [LT⁻¹/²]