Questions and Answers of College Physics A Strategic Approach 2nd

The New England Merchants Bank Building in Boston is 152 m high. On windy days it sways with a frequency of 0.17 Hz, and the acceleration of the top of the building can reach 2.0% of the free-fall
If you want to play a tune on wine glasses, you'll need to adjust the oscillation frequencies by adding water to the glasses. This changes the mass that oscillates (more water means more mass) but
Sprinters push off from the ball of their foot, then bend their knee to bring their foot up close to the body as they swing their leg forward for the next stride. Why is this an effective strategy
Gibbons move through the trees by swinging from successive handholds, as we have seen. To increase their speed, gibbons may bring their legs close to their bodies. How does this help them move more
Humans have a range of hearing of approximately 20 Hz to 20 kHz. Mice have auditory systems similar to humans, but all of the physical elements are smaller. Given this, would you expect mice to have
A person driving a truck on a "washboard" road, one with regularly spaced bumps, notices an interesting effect: When the truck travels at low speed, the amplitude of the vertical motion of the car is
A 507 g mass oscillates with an amplitude of 10.0 cm on a spring whose spring constant is 20.0 N/m. Determine:a. The period. b. The maximum speed.c. The total energy.
Figure Q14.23 represents the motion of a mass on a spring.a. What is the period of this oscillation? A. 12 s B. 24 s C. 36 s D. 48 s E. 50 sb. What is the amplitude of the oscillation? A. 1.0
We've seen that stout tendons in the legs of hopping kangaroos store energy. When a kangaroo lands, much of the kinetic energy of motion is converted to elastic energy as the tendons stretch,
If you carry heavy weights in your hands, how will this affect the natural frequency at which your arms swing back and forth? A. The frequency will increase. B. The frequency will stay the
Suppose you travel to the moon, and you take with you two timepieces: a pendulum clock and a wristwatch that runs with a wheel and a mainspring. (The wheel and spring work, essentially, like a mass
The free-fall acceleration on the moon is 1.62 m/s2. What is the length of a pendulum whose period on the moon matches the period of a 2.00-m-long pendulum on the earth?
Very loud sounds can damage hearing by injuring the vibration-sensing hair cells on the basilar membrane. Suppose a person has injured hair cells on a segment of the basilar mem- brane close to the
A building is being knocked down with a wrecking ball, which is a big metal sphere that swings on a 10-m-long cable. You are (unwisely!) standing directly beneath the point from which the wrecking
A pendulum clock keeps time by the swinging of a uniform solid rod pivoted at one end. The angular position of the rod is given by θ(t) = (0.175 rad) sin(πt), where t is in seconds. a. What is the
You and your friends find a rope that hangs down 15 m from a high tree branch right at the edge of a river. You find that you can run, grab the rope, and swing out over the river. You run at 2.0 m/s
A thin, circular hoop with a radius of 0.22 m is hanging from its rim on a nail. When pulled to the side and released, the hoop swings back and forth as a physical pendulum. The moment of inertia of
When you drive your car over a bump, the springs connecting the wheels to the car compress. Your shock absorbers then damp the subsequent oscillation, keeping your car from bouncing up and down on
A small earthquake starts a lamppost vibrating back and forth. The amplitude of the vibration of the top of the lamp- post is 6.5 cm at the moment the quake stops, and 8.0 s later it is 1.8 cm. a.
Your car rides on springs, so it will have a natural frequency of oscillation. Figure P14.40 shows data for the amplitude of motion of a car driven at different frequencies. The car is driven at 20
A 25 kg child sits on a 2.0-m-long rope swing. You are going to give the child a small, brief push at regular intervals. If you want to increase the amplitude of her motion as quickly as possible,
A spring has an unstretched length of 12 cm. When an 80 g ball is hung from it, the length increases by 4.0 cm. Then the ball is pulled down another 4.0 cm and released. a. What is the spring
A 0.40 kg ball is suspended from a spring with spring constant 12 N/m. If the ball is pulled down 0.20 m from the equilibrium position and released, what is its maximum speed while it oscillates?
As we've seen, astronauts measure their mass by measuring the period of oscillation when sitting in a chair connected to a spring. The Body Mass Measurement Device on Skylab, a 1970s space station,
Two 50 g blocks are held 30 cm above a table. As shown in Figure P14.59, one of them is just touching a 30-cm-long spring. The blocks are released at the same time. The block on the left hits the
Four people with a combined mass of 300 kg are riding in a 1100 kg car. When they drive down a washboard road with bumps spaced 5.0 m apart, they notice that the car bounces up and down with a
Bungee Man is a superhero who does super deeds with the help of Super Bungee cords. The Super Bungee cords act like ideal springs no matter how much they are stretched. One day, Bungee Man stopped a
The earth's free-fall acceleration varies from 9.78 m/s2 at the equator to 9.83 m/s2 at the poles. A pendulum whose length is precisely 1.000 m can be used to measure g. Such a device is called a
A pendulum clock has a heavy bob supported on a very thin steel rod that is 1.00000 m long at 20°C. a. To 6 significant figures, what is the clock's period? Assume that g is 9.80 m/s2 exactly. b.
A pendulum consists of a massless, rigid rod with a mass at one end. The other end is pivoted on a frictionless pivot so that it can turn through a complete circle. The pendulum is inverted, so the
a. In your own words, define what a transverse wave is. b. Give an example of a wave that, from your own experience. you know is a transverse wave. What observations or evidence tells you this is a
The wave speed on a string under tension is 200 m/s. What is the speed if the tension is doubled?
a. In your own words, define what a longitudinal wave is. b. Give an example of a wave that, from your own experience, you know is a longitudinal wave. What observations or evidence tells you this
A wave travels along a string at a speed of 280 m/s. What will be the speed if the string is replaced by one made of the same material and under the same tension but having twice the radius?
The back wall of an auditorium is 26.0 m from the stage. If you are seated in the middle row, how much time elapses between a sound from the stage reaching your ear directly and the same sound
An ultrasonic range finder sends out a pulse of ultrasound and measures the time between the emission of the pulse and the return of an echo from an object. This time is used to determine the
In an early test of sound propagation through the ocean, an underwater explosion of 1 pound of dynamite in the Bahamas was detected 3200 km away on the coast of Africa. How much time elapsed between
A thermostat on the wall of your house keeps track of the air temperature. This simple approach is of little use in the large volume of a covered sports stadium, but there are systems that determine
Figure Q15.9 shows a history graph of the motion of one point on a string as a wave traveling to the left passes by. Sketch a snapshot graph for this wave. A FIGURE Q15.9
When water freezes, the density decreases and the bonds between molecules become stronger. Do you expect the speed of sound to be greater in liquid water or in water ice?
Figure P15.10 is a history graph at x = 2 m of a wave moving to the left at 1 m/s. Draw the snapshot graph of this wave at 1 = 0 s. y (cm) -2-1 -1- FIGURE P15.10 1 2 3 4 5 6 -1 (s)
A sinusoidal wave has period 0.20 s and wavelength 2.0 m. What is the wave speed?
A sinusoidal wave travels with speed 200 m/s. Its wave- length is 4.0 m. What is its frequency?
When you want to "snap" a towel, the best way to wrap the towel is so that the end that you hold and shake is thick, and the far end is thin. When you shake the thick end, a wave travels down the
Figure P15.18 is a history graph at x = 0 m of a wave moving to the right at 2 m/s. What are the amplitude, frequency, and wavelength of this wave? y (cm) 3 -3- -6 0.2/0.4 0.6 0.8/1.0 FIGURE
The volume control on your stereo is likely designed so that each time you turn it by one click, the loudness increases by a certain number of dB. Does each click increase the output power by a fixed
A bullet can travel at a speed of over 1000 m/s. When a bullet is fired from a rifle, the actual firing makes a distinctive sound, but people at a distance may hear a second, different sound that is
A boat is traveling at 4.0 m/s in the same direction as an ocean wave of wavelength 30 m and speed 6.8 m/s. If the boat is on the crest of a wave, how much time will elapse until the boat is next on
Denver, Colorado, has an oldies station that calls itself "KOOL 105." This means that they broadcast radio waves at a frequency of 105 MHz. Suppose that they decide to describe their station by its
Figure Q16.6 shows a standing wave on a string that is oscillating at frequency fo. How many antinodes will there be if the frequency is doubled to 2fo? Explain. FIGURE Q16.6
Solar cells convert the energy of incoming light to electric energy; a good quality cell operates at an efficiency of 15%. Each person in the United States uses energy (for lighting, heating,
Figure Q16.7 shows a standing sound wave in a tube of air that is open at both ends.a. Which mode (value of m) standing wave is this?b. Is the air vibrating horizontall y or vertically? FIGURE Q16.7
You are holding one end of an elastic cord that is fastened to a wall 3.0 m away. You begin shaking the end of the cord at 3.5 Hz, creating a continuous sinusoidal wave of wavelength 1.0 m. How much
A typical flute is about 66 cm long. A piccolo is a very similar instrument, though it is smaller, with a length of about 32 cm. How does the pitch of a piccolo compare to that of a flute?
Some pipes on a pipe organ are open at both ends, others are closed at one end. For pipes that play low-frequency notes, there is an advantage to using pipes that are closed at one end. What is the
A bass guitar string is 89 cm long with a fundamental frequency of 30 Hz. What is the wave speed on this string?
A flute player tunes her instrument when the air (and the flute) is cold. As she plays, the flute and the air inside it warm up. Both the changing speed of sound in the air inside and the thermal
The fundamental frequency of a guitar string is 384 Hz. What is the fundamental frequency if the tension in the string is halved?
A friend's voice sounds different over the telephone than it does in person. This is because telephones do not transmit frequencies over about 3000 Hz. 3000 Hz is well above the normal frequency of
Suppose you were to play a trumpet after breathing helium, in which the speed of sound is much greater than in air. Would the pitch of the instrument be higher or lower than normal, or would it be
A 121-cm-long, 4.00 g string oscillates in its m = 3 mode with a frequency of 180 Hz and a maximum amplitude of 5.00 mm. What are (a) the wavelength and (b) the tension in the string?
A guitar string with a linear density of 2.0 g/m is stretched between supports that are 60 cm apart. The string is observed to form a standing wave with three antinodes when driven at a frequency of
When you speak after breathing helium, in which the speed of sound is much greater than in air, your voice sounds quite different. The frequencies emitted by your vocal cords do not change since they
A violin string has a standard length of 32.8 cm. It sounds the musical note A (440 Hz) when played without fingering. How far from the end of the string should you place your finger to play the note
Sopranos can sing notes at very high frequencies-over 1000 Hz. When they sing such high notes, it can be difficult to understand the words they are singing. Use the concepts of harmonics and formants
When you hit a baseball with a bat, the bat flexes and then vibrates. We can model this vibration as a transverse standing wave. The modes of this standing wave are similar to the modes of a
The lowest frequency in the audible range is 20 Hz. (a) What are the lengths of (a) the shortest open-open tube and (b) the shortest open-closed tube needed to produce this frequency?
If a cold gives you a stuffed-up nose, it changes the way your voice sounds, even if your vocal cords are not affected. Explain why this is so.
The contrabassoon is the wind instrument capable of sounding the lowest pitch in an orchestra. It is folded over several times to fit its impressive 18 ft length into a reasonable size
A small boy and a grown woman both speak at approximately the same pitch. Nonetheless, it's easy to tell which is which from listening to the sounds of their voices. How are you able to make this
Refer to the snapshot graph Figure Q 16.20.At t = 1 s, what is the displacement y of the string at x = 7 cm?A. -1.0 mm B. 0mm C. 0.5 mmD. 1.0 mmE. 2.0 mm y (mm) 3. v = +6 cm/s FIGURE
Refer to the snapshot graph Figure Q 16.20.At x = 3 cm, what is the earliest time that y will equal 2 mm? A. 0.5 s B. 0.7 s C. 1.0 s D. 1.5 s E. 2.5 S y (mm) 3- v = +6 cm/s FIGURE
The lowest pedal note on a large pipe organ has a fundamental frequency of 16 Hz. This extreme bass note is more felt as a rumble than heard with the ears. What is the length of the open- closed pipe
In addition to producing images, ultrasound can be used to heat tissues of the body for therapeutic purposes. When a sound wave hits the boundary between soft tissue and air, or between soft tissue
An experimenter finds that standing waves on a 0.80-m-long string, fixed at both ends, occur at 24 Hz and 32 Hz, but at no frequencies in between. a. What is the fundamental frequency? b. What is
A 75 g bungee cord has an equilibrium length of 1.2 m. The cord is stretched to a length of 1.8 m, then vibrated at 20 Hz. This produces a standing wave with two antinodes. What is the spring
An oil film on top of water has one patch that is much thinner than the wavelength of visible light. The index of refraction of the oil is less than that of water. Will the reflection from that
A 1.0-cm-wide diffraction grating has 1000 slits. It is illuminated by light of wavelength 550 nm. What are the angles of the first two diffraction orders?
Should the antireflection coating of a microscope objective lens designed for use with ultraviolet light be thinner, thicker, or the same thickness as the coating on a lens designed for visible light?
A lab technician uses laser light with a wavelength of 670 nm to test a diffraction grating. When the grating is 40.0 cm from the screen, the first-order maxima appear 6.00 cm from the center of the
The human eye can readily detect wavelengths from about 400 nm to 700 nm. If white light illuminates a diffraction grating having 750 lines/mm, over what range of angles does the visible m = 1
You are standing against the wall near a corner of a large building. A friend is standing against the wall that is around the corner from you. You can't see your friend. How is it that you can hear
Light of wavelength 500 nm in air enters a glass block with index of refraction n = 1.5. When the light enters the block, which of the following properties of the light will not change? A. The speed
The frequency of a light wave in air is 4.6 x 1014 Hz. What is the wavelength of this wave after it enters a pool of water? A. 300 nm B. 490 nm C. 650 nm D. 870 nm
Looking straight downward into a rain puddle whose surface is covered with a thin film of gasoline, you notice a swirling pattern of colors caused by interference inside the gasoline film. The point
The second minimum in the diffraction pattern of a 0.10-mm- wide slit occurs at 0.70. What is the wavelength of the light?
A laser beam of wavelength 670 nm shines through a diffraction grating that has 750 lines/mm. Sketch the pattern that appears on a screen 1.0 m behind the grating, noting distances on your drawing
Because sound is a wave, it is possible to make a diffraction grating for sound from a large board with several parallel slots for the sound to go through. When 10 kHz sound waves pass through such a
Figure P18.5 shows an object O in front of a plane mirror. Use ray tracing to determine from which locations A-D the object's image is visible. FIGURE P18.5 Mirror ΤΑ B 0 C D
The change in color when acetone is placed on the wing is due to the difference between the indices of refraction of acetone and air. Consider light of some particular color. In acetone, A. The
A ray of light impinges on a mirror as shown in Figure P18.8. A second mirror is fastened at 90 to the first.a. After striking both mirrors, at what angle relative to the incoming ray does the
A swim mask has a pocket of air between your eyes and the flat glass front. a. If you look at a fish while swimming underwater with a swim mask on, does the fish appear closer or farther than it
A convex mirror, like the passenger-side rearview mirror on a car, has a focal length of 2.0 m. An object is 4.0 m from the mirror. Use ray tracing to determine the location of its image. Is the
Iontophoresis is a noninvasive process that transports drugs through the skin without needles. In the photo, the red electrode is positive and the black electrode is negative. The electric field
A protein molecule in an electrophoresis gel has a negative charge. The exact charge depends on the pH of the solution, but 30 excess electrons is typical. What is the magnitude of the electric force
When you stand on a bathroom scale, it reads 700 N. Suppose a giant vacuum cleaner sucks half the air out of the room, reducing the pressure to 0.5 atm. Would the scale reading increase, decrease, or
Suppose you stand on a bathroom scale that is on the bottom of a swimming pool. The water comes up to your waist. Does the scale read more, less, or the same as your true weight? Explain.
When you place an egg in water, it sinks. If you add salt to the water, after some time the egg floats. Explain.
Submerged submarines contain tanks filled with water. To rise to the surface, compressed air is used to force the water out of the tanks. Explain why this works.
A cargo barge is loaded in a saltwater harbor for a trip up a freshwater river. If the rectangular barge is 3.0 m by 20.0 m and sits 0.80 m deep in the harbor, how deep will it sit in the river?

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