Concept explainers
BIO Ultrasound in Medicine. A 2.00-MHZ sound wave travels through a pregnant woman’s abdomen and is reflected from the fetal heart wall of her unborn baby. The heart wall is moving toward the sound receiver as the heart beats. The reflected sound is then mixed with the transmitted sound, and 72 beats per second are detected. The speed of sound in body tissue is 1500 m/s. Calculate the speed of the fetal heart wall at the instant this measurement is made.
Want to see the full answer?
Check out a sample textbook solutionChapter 16 Solutions
University Physics with Modern Physics (14th Edition)
Additional Science Textbook Solutions
Applications and Investigations in Earth Science (9th Edition)
Concepts of Genetics (12th Edition)
Genetic Analysis: An Integrated Approach (3rd Edition)
Biology: Life on Earth with Physiology (11th Edition)
Organic Chemistry (8th Edition)
Chemistry: Structure and Properties (2nd Edition)
- Female Aedes aegypti mosquitoes emit a buzz at about 4.00102 Hz, whereas male A. aegypti mosquitoes typically emit a buzz at about 6.00102 Hz. As a female mosquito is approaching a stationary male mosquito, is it possible that he mistakes the female for a male because of the Doppler shift of the sound she emits? How fast would the female have to be traveling relative to the male for him to make this mistake? Assume the speed of sound in the air is 343 m/s.arrow_forwardA sound wave in air has a pressure amplitude equal to 4.00 103 Pa. Calculate the displacement amplitude of the wave at a frequency of 10.0 kHz.arrow_forwardA sound wave traveling in air has a pressure amplitude of 0.5 Pa. What is the intensity of the wave?arrow_forward
- On a particular day the speed of sound in air is 340 m/s. If a plane flies at a speed of 680 m/s, is its Mach number (a) 1.5, (b) 2.0, (c) 2.5, or (d) 2.7?arrow_forwardA sound wave can be characterized as (a) a transverse wave, (b) a longitudinal wave, (c) a transverse wave or a longitudinal wave, depending on the nature of its source, (d) one that carries no energy, or (e) a wave that does not require a medium to be transmitted from one place to the other.arrow_forwardDuring a thunderstorm, a frightened child is soothed by learning to estimate the distance to a lightning strike by counting the time between seeing the lightning and hearing the thunder (Fig. P2.25). The speed vs of sound in air depends on the air temperature, but assume the value is 343 m/s. The speed of light c is 3.00 108 m/s. a. A child sees the lightning and then counts to eight slowly before hearing the thunder. Assume the light travel time is negligible. Estimate the distance to the lightning strike. b. Using your estimate in part (a), find the light travel time. Is it fair to neglect the light travel time? c. Think about how time was measured in this problem. Is it fair to neglect the difference between the speed of sound in cold air (vs at 0C = 331.4 m/s) and the speed of sound in very warm air (vs at 40C = 355.4 m/s)?arrow_forward
- A siren emits a sound of frequency 1.44103 Hz when it is stationary with respect to an observer. The siren is moving away from a person and toward a cliff at a speed of 15 m/s. Both the cliff and the observer are at rest. Assume the speed of sound in air is 343 m/s. What is the frequency of the sound that the person will hear a. coming directly from the siren and b. reflected from the cliff?arrow_forwardA bat emits a sound at a frequency of 30.0 kHz as it approaches a wall. The bat detects beats such that the frequency of the echo is 900 Hz higher than the frequency the bat is emitting. The speed of sound in air is 340 m/s. The speed of the bat is closest toarrow_forwardSound is detected when a sound wave causes the eardrum to vibrate. Typically, the diameter of the eardrum is about 8.0mm in humans. When someone yells to you in a noisy environment, the sound intensity at your ear sometimes approximates 2 x 10-6 W/m2. Suppose that the 2 x 10-6 W/m2 of sound you are hearing comes from a janitor cleaning a rug by pulling a vacuum cleaner (at the end of a 1-meter-long tube oriented perpendicularly to the line separating you from the janitor). This person is yelling just over the din of the appliance in order to be heard by you. Estimate the distance between you and the janitorarrow_forward
- We use ultrasound to measure the diameter of a cuvette filled with water and obtain a value of 2.3 cm. For an object made of an unknown substance but having the same diameter, the ultrasound measurement yields a diameter of 1.5 cm. If the speed of sound of water is 1530 m/s, how many m/s is the speed of sound in the given substance? Speed of sound [m/s)arrow_forwardYou are standing on a train station platform as a train goes by close to you. As the train approaches, you hear the whistle sound at a frequency of f1 = 93 Hz. As the train recedes, you hear the whistle sound at a frequency of f2 = 75 Hz. Take the speed of sound in air to be v = 340 m/s. (a) Find an equation for the speed of the sound source vs, in this case it is the speed of the train. Express your answer in terms of f1, f2, and v. (b) Find the numeric value, in meters per second, for the speed of the train. (c) Find an equation for the frequency of the train whistle fs ("s" is for "source") that you would hear if the train were not moving. Express your answer in terms of f1, f2, and v. (d) Find the numeric value, in hertz, for the frequency of the train whistle fs that you would hear if the train were not moving.arrow_forwardThe intensity of sound is measured on the decibel scale, dB. The equation dB=10logI represents the decibel level, where I is the ratio of the sound to the human hearing threshold.On a construction site, a large sheet of steel is dropped on the ground. The noise it makes is 100,000 times greater than the human hearing threshold. To the nearest whole number, what is the decibel value of the noise?arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningUniversity Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice University
- An Introduction to Physical SciencePhysicsISBN:9781305079137Author:James Shipman, Jerry D. Wilson, Charles A. Higgins, Omar TorresPublisher:Cengage Learning