Energy carried by a sinusoidal string wave
Energy transport grows with squared amplitude and frequency in the linear model.
Key knowledge
For one travelling sinusoidal small-transverse-displacement wave on a uniform taut ideal string, average transmitted mechanical power is μA²ω²v/2, with v=√(Tension/μ). Doubling amplitude at fixed frequency and string parameters quadruples this average power. This is energy flow along the string, rather than the transverse particle speed.
Values and equations
P_average=½μA²ω²v; v=√(Tension/μ)
- P_average
- Time-averaged one-way mechanical power W
- μ
- String mass per unit length kg m⁻¹
- A
- Transverse displacement amplitude m
- ω
- Angular frequency rad s⁻¹
- v
- Wave phase speed m s⁻¹
- Tension
- String tension magnitude N
Conditions and scope
- Positive uniform linear mass density and tension; small slopes, negligible bending stiffness/damping and a single travelling wave.
- Counterpropagating waves form interference/standing-wave patterns; their local energy and net flux must be combined using the field, not by assuming this one-wave power formula for every pattern.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Read §16.4 travelling-string kinetic/potential-energy sums and average power16.20. No claim that arbitrary standing-wave stored energy is a one-way energy current.
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Entry details
Permanent link to this entry ↗- Record identity
- foundation-physics-string-wave-power
- Revision
- foundations-refresh.1
- Structured reference record
- Foundational reference additions