Essential University Physics (3rd Edition)
3rd Edition
ISBN: 9780134202709
Author: Richard Wolfson
Publisher: PEARSON
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Chapter 14, Problem 74P
Obstetricians use ultrasound to monitor fetal heartbeat. If 5.0-MHz ultrasound reflects off the moving heart wall with a 100-Hz frequency shift, what’s the speed of the heart wall? (Hint: You have two shifts to consider.)
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Sound waves entering human ear first pass through the auditory canal before reaching the eardrum. If a typical adult has an auditory canal of 2.5cm long and 7.0mm in diameter, suppose that when you listen to ordinary conversation, the intensity of sound waves is about 3.2 × 10^−6W/m^2;
a) What is the average power delivered to the eardrum?
On a 20°C°C night, a bat hovering in the air emits an ultrasonic chirp that has a
frequency of 45 kHzkHz. It hears an echo 60 msms later.
Suppose the object is an insect flying straight away from the bat. What is the
insect's speed if the ultrasonic echo is shifted down in frequency by 750 Hz?
An ultrasonic scan uses the echo waves coming from something moving (such as the beating heart of a fetus) inside the body and the waves that are directly received from the transmitter to form a measurable beat frequency. This allows the speed of the internal structure to be isolated and analyzed. The speed of the ultrasound waves in tissue is about 1540 m/s.
What is the beat frequency ?beats detected when waves with a frequency of 3.80 MHz are used to scan a fetal heartbeat (moving at a speed of ±8.50 cm/s)?
hint that came with it:
In this problem there's a stationary source of ultrasound that reflects sound off of a moving object which then returns back to the ultrasound device to measure the frequency. There are 2 Doppler shifts that need to be considered. First the stationary source and the moving observer. Second, when the sound reflects off, the moving object now becomes the source and the ultrasound device becomes the observer. In this shift, the frequency measured by the…
Chapter 14 Solutions
Essential University Physics (3rd Edition)
Ch. 14.1 - A boat bobs up and down on a water wave, moving 2...Ch. 14.2 - The figure shows snapshots of two waves...Ch. 14.3 - Two identical stars are different distances from...Ch. 14.4 - Your band needs a new guitar amplifier, and the...Ch. 14.5 - Light shines through two small holes into a dark...Ch. 14.6 - Youre holding one end of a taut rope, and you cant...Ch. 14.7 - A string 1 m long is clamped tightly at one end...Ch. 14.8 - In Fig. 14.35, which is moving faster in relation...Ch. 14 - What distinguishes a wave from an oscillation?Ch. 14 - Red light has a longer wavelength than blue light....
Ch. 14 - Prob. 3FTDCh. 14 - As a wave propagates on a string, the string moves...Ch. 14 - If you doubled the tension in a string, what would...Ch. 14 - A heavy cable is hanging vertically, its bottom...Ch. 14 - Prob. 7FTDCh. 14 - Medical ultrasound uses frequencies around 107 Hz,...Ch. 14 - If you double the pressure of a gas while keeping...Ch. 14 - Water is about a thousand times more dense than...Ch. 14 - Prob. 11FTDCh. 14 - When a wave source moves relative to the medium, a...Ch. 14 - Why can a boat easily produce a shock wave on the...Ch. 14 - Ocean waves with 18-m wavelength travel at 5.3...Ch. 14 - Prob. 15ECh. 14 - Prob. 16ECh. 14 - Prob. 17ECh. 14 - A seismograph located 1250 km from an earthquake...Ch. 14 - Medical ultrasound waves travel at about 1500 m/s...Ch. 14 - An ocean wave has period 4.1 s and wavelength 10.8...Ch. 14 - Find the (a) amplitude, (b) wavelength, (c)...Ch. 14 - Ultrasound used in a medical imager has frequency...Ch. 14 - Prob. 23ECh. 14 - Prob. 24ECh. 14 - Prob. 25ECh. 14 - A transverse wave 1.2 cm in amplitude propagates...Ch. 14 - A transverse wave with 3.0-cm amplitude and 75-cm...Ch. 14 - Prob. 28ECh. 14 - Prob. 29ECh. 14 - Show that P/ from Equation 14.9 has the units of...Ch. 14 - Find the sound speed in air under standard...Ch. 14 - Timers in sprint races start their watches when...Ch. 14 - The factor for nitrogen dioxide (NO2) is 1.29....Ch. 14 - A gas with density 1.0 kg/m3 and pressure 81 kN/m2...Ch. 14 - Prob. 35ECh. 14 - Youre flying in a twin-engine turboprop aircraft,...Ch. 14 - Prob. 37ECh. 14 - A 2.0-m-long string is clamped at both ends. (a)...Ch. 14 - When a stretched string is clamped at both ends,...Ch. 14 - A string is clamped at both ends and tensioned...Ch. 14 - A crude model of the human vocal tract treats it...Ch. 14 - A car horn emits 380-Hz sound. If the car moves at...Ch. 14 - A fire stations siren is blaring at 85 Hz. Whats...Ch. 14 - A fire trucks siren at rest wails at 1400 Hz;...Ch. 14 - Red light emitted by hydrogen atoms at rest in the...Ch. 14 - Figure 14.36 shows a simple harmonic wave at time...Ch. 14 - Prob. 47PCh. 14 - Prob. 48PCh. 14 - Figure 14.37 shows a wave train consisting of two...Ch. 14 - A loudspeaker emits energy at the rate of 50 W,...Ch. 14 - Prob. 51PCh. 14 - Prob. 52PCh. 14 - Prob. 53PCh. 14 - A wire is under 32.8-N tension, carrying a wave...Ch. 14 - A spring of mass m and spring constant k has an...Ch. 14 - Prob. 56PCh. 14 - Prob. 57PCh. 14 - Figure 14.38 shows two observers 20 m apart on a...Ch. 14 - An ideal spring is stretched to a total length L1....Ch. 14 - Prob. 60PCh. 14 - You see an airplane 5.2 km straight overhead....Ch. 14 - What are the intensities in W/m2 of sound with...Ch. 14 - Show that a doubling of sound intensity...Ch. 14 - Sound intensity from a localized source decreases...Ch. 14 - At 2.0 in from a localized sound source you...Ch. 14 - The A-string (440 Hz) on a piano is 38.9 cm long...Ch. 14 - Prob. 67PCh. 14 - Youre designing an organ for a new concert hall;...Ch. 14 - Show by differentiation and substitution that a...Ch. 14 - Prob. 70PCh. 14 - Youre a marine biologist concerned with the effect...Ch. 14 - A 2.25-m-long pipe has one end open. Among its...Ch. 14 - Prob. 73PCh. 14 - Obstetricians use ultrasound to monitor fetal...Ch. 14 - Prob. 75PCh. 14 - You move at speed u toward a wave source thats...Ch. 14 - Youre a meteorologist specifying a new Doppler...Ch. 14 - Use a computer to form the sum implied in the...Ch. 14 - Your little sister and her friend build treehouses...Ch. 14 - An airport neighborhood is concerned about the...Ch. 14 - Tsunamis are ocean waves generally produced when...Ch. 14 - Tsunamis are ocean waves generally produced when...Ch. 14 - Tsunamis are ocean waves generally produced when...Ch. 14 - Tsunamis are ocean waves generally produced when...
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