Exam 13: Mechanical Waves

An earthquake emits both S-waves and P-waves which travel at different speeds through the Earth.A P-wave travels at 9 000 m/s and an S-wave travels at 5 000 m/s.If P-waves are received at a seismic station 1.00 minute before an S-wave arrives,how far away is the earthquake center?

Exhibit 16-3 Four wave functions are given below. I. y(x,t)= 5sin(4x - 20t + 4) II. y(x,t)= 5sin(3x - 12t + 5) III. y(x,t)= 5cos(4x + 24t + 6) IV. y(x,t)= 14cos(2x - 8t + 3) Use this exhibit to answer the following question. -Refer to Exhibit 16-3.Rank the wave functions in order of the magnitude of the wave speeds,from least to greatest.

A piano wire of length 1.5 m vibrates so that one-half wavelength is contained on the string.If the frequency of vibration is 65 Hz,the amplitude of vibration is 3.0 mm,and the density is 15 g/m,how much energy is transmitted per second down the wire?

Bats can detect small objects such as insects that are of a size on the order of a wavelength.If bats emit a chirp at a frequency of 60 kHz and the speed of soundwaves in air is 330 m/s,what is the smallest size insect they can detect?

An airplane traveling at half the speed of sound emits sound at a frequency of 5 000 Hz.At what frequency does a stationary listener hear the sound as the plane approaches,and after it passes by? Assume the airplane is not flying very high.

Ocean waves with a wavelength of 120 m are coming in at a rate of 8 per minute.What is their speed?

A car approaches a stationary police car at 36 m/s.The frequency of the siren (relative to the police car)is 500 Hz.What is the frequency (in Hz)heard by an observer in the moving car as he approaches the police car? (Assume the velocity of sound in air is 343 m/s. )

A truck moving at 36 m/s passes a police car moving at 45 m/s in the opposite direction.If the frequency of the siren relative to the police car is 500 Hz,what is the frequency heard by an observer in the truck as the police car approaches the truck? (The speed of sound in air is 343 m/s. )

If the breakers at a beach are separated by 5.0 m and hit shore with a frequency of 0.20 Hz,with what speed are they traveling?

The variation in the pressure of helium gas,measured from its equilibrium value,is given by $\Delta$ P = 2.9 *10 ^{- 5} cos (6.20x - 3 000t)where x and t have units m and s.Determine the speed (in m/s)of the wave.

Exhibit 16-1 The figure below shows a sine wave at one point of a string as a function of time. Use the exhibit to answer the following question. -Refer to Exhibit 16-1.Which of the graphs below shows a wave where the amplitude and frequency are each reduced in half?

What is the expression for the transverse velocity of the wave in a string given by $y = A \sin ( k x - ? t )$ ?

The figure below represents a string which has a heavy section and a light section.The mass per unit length of the heavy section is 16 times as large as the mass per unit length of the light section.When the string is under tension,the speed of a pulse traveling in the heavy section is ____ times the speed of that same pulse traveling in the light section.

While you are sounding a tone on a toy whistle,you notice a friend running toward you.If you want her to hear the same frequency that you hear even though she is approaching,you must

Exhibit 16-2 The figure below shows a sine wave on a string at one instant of time. Use this exhibit to answer the following question(s). -Refer to Exhibit 16-2.Which of the graphs below shows a wave where the wavelength is twice as large?

Exhibit 16-1 The figure below shows a sine wave at one point of a string as a function of time. Use the exhibit to answer the following question. -Refer to Exhibit 16-1.Which of the graphs below shows a wave where the amplitude and the frequency are doubled?

A friend hands you an equation sheet with the following equation for the Doppler effect: $f ^ { \prime } = \frac { \left( v - v _ { 0 } \right) } { \left( v + v _ { s } \right) } f$ .This version of the equation is correct with signs as given only if

Find the period of a wave of 100-m wavelength in deep water where $\nu = \sqrt { g \lambda / 2 \pi }$ .

Exhibit 16-3 Four wave functions are given below. I. y(x,t)= 5sin(4x - 20t + 4) II. y(x,t)= 5sin(3x - 12t + 5) III. y(x,t)= 5cos(4x + 24t + 6) IV. y(x,t)= 14cos(2x - 8t + 3) Use this exhibit to answer the following question. -Refer to Exhibit 16-3.Rank the wave functions in order of the magnitude of the frequencies of the waves,from least to greatest.

A bat,flying at 5.00 m/s,emits a chirp at 40.0 kHz.If this sound pulse is reflected by a wall,what is the frequency of the echo received by the bat? (v_sound = 340 m/s. )