- #1
masterchiefo
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Homework Statement
An incident wave frequency f =500Hz , power Wi = 50 W and amplitude Ai= 5 mm spreads to the positive x in a linear density rope u1 unknown. When the wave encounters another rope ( attached to the first at a point P) density linear u2= 64 g/m (such as u2>u1 ) , The transmitted wave has a power Wt = 32 Watts.
a) Determine u1, and the value of the impedance Z1 and Z2.
Homework Equations
The Attempt at a Solution
64g/m = 0.064kg/m
5 mm = 0.005 m
T = Wt/Wi
T= 32/50
T = 0.64
R + T = 1 => R + 0.64 = 1
R = 0.36
R = r2
0.36 = r2
r = 0.6
Ar = r*Ai
Ar = 0.6 * 0.005
Ar = 0.003
sqrt(u1)/sqrt(u2) = (Ai + Ar)/ (Ai - Ar)
sqrt(u1)/sqrt(0.064) = (0.005 + 0.003)/ (0.005 - 0.003)
u1 = 0.1024
Something is wrong and I can't figure it out, I know its wrong because it says u2 has to be bigger than u1, and my answer of u1 is bigger than u2.
thanks.