Answer to Question #262353 in Physics for HAMBA

Question

A violin string 15.0cm long and fixed at both ends oscillates in its n=1 mode. The

speed of waves on the string is 250ms-1 and the speed of sound in air is 348ms-1. Find,

(i)the frequency of the waves

(ii)the wavelength of the emitted sound.

(b)A closed organ pipe 60cm long and of cross-sectional area 50cm2 is resonating at its

fundamental frequency. If the amplitude of the air at the open end is 0.20cm, find the

acoustic power radiated.

(c)A plane sound wave traveling through air has maximum acoustic pressure

of 10-2Nm-2. If the speed of sound is 343ms-1, and the density is 1.29kgm-3, find the

average kinetic energy density of the gas.

Answer 1

i) $f=v/(2L)=833\text{ Hz}.$

ii) $\lambda=c/f=348/833=0.42\text{ m}.$

(c) $w_k=p^2/(2\rho c^2)=3.29·10^{-10}\text{ J/m}^3.$