Concept explainers
BIO Resonance vibration transfer and the ear When you push a person on a swing, a series of snail pushes timed to match the swinger's swinging frequency makes the person swing with larger amplitude if timed differently, the pushing is ineffective. The board shown in Figure 10.17 (from the Exploratorium in San Francisco) is made of rods of different length with identical balls on the ends of each rod Each rod vibrates at a different natural frequency, the long rod on the left at lower frequency and the short rod on the right at higher frequency if you shake the board at the high frequency at which the short rod vibrates, the short rod swings with large amplitude while the others swing a little. If you shake the board at the middle frequency at which the two center rods vibrate, the center rods undergo large-amplitude vibrations and the rods on each end do not vibrate imagine now that you have a fancy board with 15,000 rods, each of slightly different length, the shortest on the left and the longest on the right Shaking the board at a particular frequency causes the rods in one small region of the board to vibrate at this frequency and has little effect on the others.
The inner ear (the cochlea) is a little Ike this fancy board. Sound reaching the tympanic membrane, or eardrum, is greatly amplified by three tiny bones in the middle ear—the hammer, anvil and stirrup (Figure 10.18) These bores vibrate, pushing on the find in the inner ear and causing vibrations along its entire length A basilar membrane with about 15.000 hair cells passes along the center of the inner ear. The basilar membrane is narrow and stiff near the entrance to the inner car and wide and more flexible near the end. When a single-frequency vibration causes the fluid to vibrate, the membrane and the hair cells respond best at a single place—high frequencies near the oval widow and low frequencies near the end of the basilar membrane The bending of these hairs causes those nerve cells to fire. Thus, we detect the frequency of the sound by the part of the membrane from which the nerve signal comes.
If you were to shake the special board (the one that has 15,000 rods of varying length) at one particular frequency, then what would happen? a. None of the rods would vibrate. b. All of the rods would vibrate. c. A small number of rods at one location would vibrate. d. A disturbance would travel back and forth along the board.
Want to see the full answer?
Check out a sample textbook solutionChapter 10 Solutions
College Physics
Additional Science Textbook Solutions
Physics (5th Edition)
Essential University Physics (3rd Edition)
Conceptual Integrated Science
Physics: Principles with Applications
Applied Physics (11th Edition)
- How would a car bounce after a bump under each of these conditions? (a) overdamping (b) underdamping (c) critical dampingarrow_forwardSuppose you have a 0.750kg object on a horizontal surface connected to a spring that has a force constant of 150N/m. There is simple friction between me object and surface with a static coefficient of friction =0.100. (a) How far can the spring be stretched without moving the mass? (b) If the object is set into oscillation with an amplitude twice the distance found in part (a), and me kinetic coefficient of friction is k=0.0850, what total distance does it travel before stopping? Assume it starts at me maximum amplitude.arrow_forwardA baby bounces up and down in her crib. Her mass is 12.5 kg, and the crib mattress can be modeled as a light spring with force constant 700 N/m. (a) The baby soon learns to bounce with maximum amplitude and minimum effort by bending her knees at what frequency? (b) If she were to use the mattress as a trampoline losing contact with it for part of each cyclewhat minimum amplitude of oscillation does she require?arrow_forward
- Is it possible to have damped oscillations when a system is at resonance? Explain.arrow_forwardIt is important for astronauts in space to monitor their body weight. In Earth orbit, a simple scale only reads an apparent weight of zero, so another method is needed. NASA developed the body mass measuring device (BMMD) for Skylab astronauts. The BMMD is a spring-mounted chair that oscillates in simple harmonic motion (Fig. P16.23). From the period of the motion, the mass of the astronaut can be calculated. In a typical system, the chair has a period of oscillation of 0.901 s when empty. The spring constant is 606 N/m. When a certain astronaut sits in the chair, the period of oscillation increases to 2.37 s. Determine the mass of the astronaut. FIGURE P16.23arrow_forwardFigure P13.74 shows a crude model of an insect wing. The mass m represents the entire mass of the wing, which pivots about the fulcrum F. The spring represents the surrounding connective tissue. Motion of the wing corresponds to vibration of the spring. Suppose the mass of the wing is 0.30 g and the effective spring constant of the tissue is 4.7 104 N/m. If the mass m moves up and down a distance of 2.0 mm from its position of equilibrium, what is the maximum speed of the outer tip of the wing? Figure P13.74arrow_forward
- The device pictured in the following figure entertains infants while keeping them from wandering. The child bounces in a harness suspended from a door frame by a spring. (a) If the spring stretches 0.250 m while supporting an 8.0-kg child, what is its force constant? (b) What is the time for one complete bounce of this child? (c) What is the child’s maximum velocity if the amplitude of her bounce is 0.200 m?arrow_forwardA piston in a gasoline engine is in simple harmonic motion. The engine is running at the rate of 3 600 rev min. Taking the extremes of its position relative to its center point as 5.00 cm, find the magnitudes of the (a) maximum velocity and (b) maximum acceleration of the piston.arrow_forwardFour people, each with a mass of 72.4 kg, are in a car with a mass of 1 130 kg. An earthquake strikes. The vertical oscillations of the ground surface make the car bounce up and down on its suspension springs, but the driver manages to pull off the road and stop. When the frequency of the shaking is 1.80 Hz, the car exhibits a maximum amplitude of vibration. The earthquake ends, and the four people leave the car as fast as they can. By what distance docs the cars undamaged suspension lift the cars body as the people get out?arrow_forward
- Explain why you expect an object made of a stiff material to vibrate at a higher frequency than a similar object made of a spongy material.arrow_forwardYou are looking at a small, leafy tree. You do not notice any breeze, and most of the leaves on the tree are motionless. One leaf however, is fluttering hack and forth wildly. After a while, that leaf stops moving and you notice a different leaf moving much more than all the others. Explain what could cause the large motion of one particular leaf.arrow_forwardA biologist hangs a sample of mass 0.725 kg on a pair of identical, vertical springs in parallel and slowly lowers the sample to equilibrium, stretching the springs by 0.200 m. Calculate the value of the spring constant of one of the springs.arrow_forward
- Glencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-HillPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- Physics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning