sound?(20點)

lina

2007-04-16 5:33 am

unless otherwise specified,take the speed of sound in air to be 340 m/s and the density of air to be 1.29 kg/m^3.
1.bats emit high-frequency sound to locate objects.the highest frequency emitted by a bat is 10^5 Hz.what is the wavelength of this signal?
2.dogs can hear sound with frequencies up to 35000 Hz.what is the wavelength of such waves?
3.the speed of longitudinal waves in a rod is given by
v=√(Y/ρ)

更新1:

3.where Y is Young's modulus.calculate the speed of sound in a steel rod for which Y=2x10^11 N/m^2 and ρ=7.8g/cm^3.

回答 (1)

用戶139100

2007-04-16 7:12 am

✔ 最佳答案

use formula:
speed of wave = frequency x wavelength
i.e. v = fλ
Question 1)
λ = v/f = 340m/s / 10^5Hz
λ = 3.4 x 10^5

Question 2)
λ = v/f = 340m/s / 35000Hz = 9.17 x 10^3

Question 3)
What is the question? to find v??

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