- #1
hobmarcus
- 10
- 0
Homework Statement
A room has two opposing walls which are tiled. The remaining walls, floors, and ceiling are lined with sound-absorbent material. The lowest frequency for which the room is acoustically resonant is 50Hz.
(a) Complex noise occurs in the room which excites only the lowest two modes, in such a way that each mode has its maximum amplitude at t=0. Sketch the appearance, fro each mode separately, of the displacement versus at t=0,t=1/200sec, and 1/100 sec.
(b) It is observed that the maximum displacement of dust particles in the air (which does not necessarily occur at the same time at each position.) at various points between walls is as follows:
what are the amplitude of each of the two separate modes?
Homework Equations
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The Attempt at a Solution
for part a, the lowest two modes are just simply 50hz and 100hz?
if yes, the equation of the complex noise is it just x=2Acos(50πt)cos(150πt)
Since ω=2πf and x=2Acos((ω1+ω2)/2)cos((ω1-ω2)/2)
for part b, I really have no clue how to approach.
Any tips or explanations, please. I appreciate any helps.