Question
(II) Show that the frequency of standing waves on a cord of length $\ell$ and linear density $\mu,$ which is stretched to a tension $F_{T, \text { is given by }}$$$f=\frac{n}{2 \ell} \sqrt{\frac{F_{\mathrm{T}}}{\mu}}$$where $n$ is an integer.
Step 1
In the fundamental case, the wavelength is twice the length of the cord, so we can write $\lambda = 2l$. Show more…
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(II) $(a)$ Show that the average rate with which energy is transported along a cord by a mechanical wave of frequency $f$ and amplitude $A$ is $$\overline{P}=2 \pi^{2} \mu v f^{2} A^{2},$$ where $v$ is the speed of the wave and $\mu$ is the mass per unit length of the cord. (b) If the cord is under a tension $F_{T}=135 \mathrm{N}$ and has mass per unit length $0.10 \mathrm{kg} / \mathrm{m},$ what power is required to transmit $120-\mathrm{Hz}$ transverse waves of amplitude 2.0 $\mathrm{cm} ?$
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