Question

ws 7
ft=1
f=frequency
t=time for one vibration
v=fλ , d=st
λ=wave length
d=distance , s= speed
t=time
distance of
vibrating thing= 4 a f t ,
a=amplitude
infrasonic< 20 hz
ultrasonic > 20,000 hz
reflection gives echo sound
sound reflect more in cooler
air than warmer air.
longitudinal waves :particles
vibrate parallel to the
direction of the motion of the
wave.
transverse waves: particles
vibrate perpendicular to the
direction of the motion of the
wave.
waves and sound chapter 8
identify the indicated parts of the wave in figure 2.

1. copy figure 5 into your notebook.

(a) label the amplitude, wavelength, and equilibrium point
of the waveform.
(b) list all pairs of points that are in phase.
practice

1. if a wave has a frequency of 230 hz and a wavelength of 2.3

m, what is its speed? t/ ans: 530 m/s

1. if a wave has a speed of 1500 m/s and a frequency of 11 hz,

what is its wavelength? t/ ans: 140 m

1. if a wave has a speed of 405 m/s and a wavelength of 2.0 m,

what is its frequency? t/ ans: 2.0 3 102 hz

Explanation:

Practice 1

Step1: Recall the wave speed formula

The formula relating wave speed (\(v\)), frequency (\(f\)) and wavelength (\(\lambda\)) is \(v = f\lambda\).

Step2: Substitute the given values

We are given \(f = 230\space Hz\) and \(\lambda= 2.3\space m\). Substituting these values into the formula: \(v=230\times2.3\).

Step3: Calculate the product

\(230\times2.3 = 529\approx530\space m/s\) (rounded to a reasonable value as per the answer).

Step1: Recall the wave speed formula

The formula is \(v = f\lambda\), we need to solve for \(\lambda\), so rearranging gives \(\lambda=\frac{v}{f}\).

Step2: Substitute the given values

We have \(v = 1500\space m/s\) and \(f = 11\space Hz\). Substituting into the formula: \(\lambda=\frac{1500}{11}\).

Step3: Calculate the division

\(\frac{1500}{11}\approx136.36\approx140\space m\) (rounded to a reasonable value as per the answer).

Step1: Recall the wave speed formula

The formula is \(v = f\lambda\), we need to solve for \(f\), so rearranging gives \(f=\frac{v}{\lambda}\).

Step2: Substitute the given values

We have \(v = 405\space m/s\) and \(\lambda = 2.0\space m\). Substituting into the formula: \(f=\frac{405}{2.0}\).

Step3: Calculate the division

\(\frac{405}{2.0}=202.5\approx203\space Hz\) (assuming a typo in the answer and it should be 203 Hz or similar, following the pattern of the answer provided).

Answer:

The speed of the wave is \(\boldsymbol{530\space m/s}\)

Practice 2