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While Carnot engines are ideal engines, in reality, no engine achieves Carnotâs theoretical maximum efficiency, since dissipative processes, such as friction, play a role. Carnot cycles without heat loss may be possible at absolute zero, but this has never been seen in nature. | https://openstax.org/books/college-physics-2e/pages/15-section-summary |
An artifact of the second law of thermodynamics is the ability to heat an interior space using a heat pump. Heat pumps compress cold ambient air and, in so doing, heat it to room temperature without violation of conservation principles. | https://openstax.org/books/college-physics-2e/pages/15-section-summary |
To calculate the heat pumpâs coefficient of performance, use the equationCOPhp=QhWCOPhp=QhW. | https://openstax.org/books/college-physics-2e/pages/15-section-summary |
A refrigerator is a heat pump; it takes warm ambient air and expands it to chill it. | https://openstax.org/books/college-physics-2e/pages/15-section-summary |
Entropy is the loss of energy available to do work. | https://openstax.org/books/college-physics-2e/pages/15-section-summary |
Another form of the second law of thermodynamics states that the total entropy of a system either increases or remains constant; it never decreases. | https://openstax.org/books/college-physics-2e/pages/15-section-summary |
Entropy is zero in a reversible process; it increases in an irreversible process. | https://openstax.org/books/college-physics-2e/pages/15-section-summary |
The ultimate fate of the universe is likely to be thermodynamic equilibrium, where the universal temperature is constant and no energy is available to do work. | https://openstax.org/books/college-physics-2e/pages/15-section-summary |
Entropy is also associated with the tendency toward disorder in a closed system. | https://openstax.org/books/college-physics-2e/pages/15-section-summary |
Disorder is far more likely than order, which can be seen statistically. | https://openstax.org/books/college-physics-2e/pages/15-section-summary |
The entropy of a system in a given state (a macrostate) can be written asS=klnW,S=klnW,wherek=1.38Ã10â23J/Kk=1.38Ã10â23J/Kis Boltzmannâs constant, andlnWlnWis the natural logarithm of the number of microstatesWWcorresponding to the given macrostate. | https://openstax.org/books/college-physics-2e/pages/15-section-summary |
amplitude : the maximum displacement from the equilibrium position of an object oscillating around the equilibrium position | https://openstax.org/books/college-physics-2e/pages/16-glossary |
antinode : the location of maximum amplitude in standing waves | https://openstax.org/books/college-physics-2e/pages/16-glossary |
beat frequency : the frequency of the amplitude fluctuations of a wave | https://openstax.org/books/college-physics-2e/pages/16-glossary |
constructive interference : when two waves arrive at the same point exactly in phase; that is, the crests of the two waves are precisely aligned, as are the troughs | https://openstax.org/books/college-physics-2e/pages/16-glossary |
critical damping : the condition in which the damping of an oscillator causes it to return as quickly as possible to its equilibrium position without oscillating back and forth about this position | https://openstax.org/books/college-physics-2e/pages/16-glossary |
deformation : displacement from equilibrium | https://openstax.org/books/college-physics-2e/pages/16-glossary |
destructive interference : when two identical waves arrive at the same point exactly out of phase; that is, precisely aligned crest to trough | https://openstax.org/books/college-physics-2e/pages/16-glossary |
elastic potential energy : potential energy stored as a result of deformation of an elastic object, such as the stretching of a spring | https://openstax.org/books/college-physics-2e/pages/16-glossary |
force constant : a constant related to the rigidity of a system: the larger the force constant, the more rigid the system; the force constant is represented byk | https://openstax.org/books/college-physics-2e/pages/16-glossary |
frequency : number of events per unit of time | https://openstax.org/books/college-physics-2e/pages/16-glossary |
fundamental frequency : the lowest frequency of a periodic waveform | https://openstax.org/books/college-physics-2e/pages/16-glossary |
intensity : power per unit area | https://openstax.org/books/college-physics-2e/pages/16-glossary |
longitudinal wave : a wave in which the disturbance is parallel to the direction of propagation | https://openstax.org/books/college-physics-2e/pages/16-glossary |
natural frequency : the frequency at which a system would oscillate if there were no driving and no damping forces | https://openstax.org/books/college-physics-2e/pages/16-glossary |
nodes : the points where the string does not move; more generally, nodes are where the wave disturbance is zero in a standing wave | https://openstax.org/books/college-physics-2e/pages/16-glossary |
oscillate : moving back and forth regularly between two points | https://openstax.org/books/college-physics-2e/pages/16-glossary |
over damping : the condition in which damping of an oscillator causes it to return to equilibrium without oscillating; oscillator moves more slowly toward equilibrium than in the critically damped system | https://openstax.org/books/college-physics-2e/pages/16-glossary |
overtones : multiples of the fundamental frequency of a sound | https://openstax.org/books/college-physics-2e/pages/16-glossary |
period : time it takes to complete one oscillation | https://openstax.org/books/college-physics-2e/pages/16-glossary |
periodic motion : motion that repeats itself at regular time intervals | https://openstax.org/books/college-physics-2e/pages/16-glossary |
resonance : the phenomenon of driving a system with a frequency equal to the system's natural frequency | https://openstax.org/books/college-physics-2e/pages/16-glossary |
resonate : a system being driven at its natural frequency | https://openstax.org/books/college-physics-2e/pages/16-glossary |
restoring force : force acting in opposition to the force caused by a deformation | https://openstax.org/books/college-physics-2e/pages/16-glossary |
simple harmonic motion : the oscillatory motion in a system where the net force can be described by Hookeâs law | https://openstax.org/books/college-physics-2e/pages/16-glossary |
simple harmonic oscillator : a device that implements Hookeâs law, such as a mass that is attached to a spring, with the other end of the spring being connected to a rigid support such as a wall | https://openstax.org/books/college-physics-2e/pages/16-glossary |
simple pendulum : an object with a small mass suspended from a light wire or string | https://openstax.org/books/college-physics-2e/pages/16-glossary |
superposition : the phenomenon that occurs when two or more waves arrive at the same point | https://openstax.org/books/college-physics-2e/pages/16-glossary |
transverse wave : a wave in which the disturbance is perpendicular to the direction of propagation | https://openstax.org/books/college-physics-2e/pages/16-glossary |
under damping : the condition in which damping of an oscillator causes it to return to equilibrium with the amplitude gradually decreasing to zero; system returns to equilibrium faster but overshoots and crosses the equilibrium position one or more times | https://openstax.org/books/college-physics-2e/pages/16-glossary |
wave : a disturbance that moves from its source and carries energy | https://openstax.org/books/college-physics-2e/pages/16-glossary |
wave velocity : the speed at which the disturbance moves. Also called the propagation velocity or propagation speed | https://openstax.org/books/college-physics-2e/pages/16-glossary |
wavelength : the distance between adjacent identical parts of a wave | https://openstax.org/books/college-physics-2e/pages/16-glossary |
An oscillation is a back and forth motion of an object between two points of deformation. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
An oscillation may create a wave, which is a disturbance that propagates from where it was created. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
The simplest type of oscillations and waves are related to systems that can be described by Hookeâs law:F=âkx,F=âkx,whereFFis the restoring force,xxis the displacement from equilibrium or deformation, andkkis the force constant of the system. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
whereFFis the restoring force,xxis the displacement from equilibrium or deformation, andkkis the force constant of the system. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Elastic potential energyPEelPEelstored in the deformation of a system that can be described by Hookeâs law is given byPEel=(1/2)kx2.PEel=(1/2)kx2. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Periodic motion is a repetitious oscillation. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
The time for one oscillation is the periodTT. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
The number of oscillations per unit time is the frequencyff. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
These quantities are related byf=1T.f=1T. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Simple harmonic motion is oscillatory motion for a system that can be described only by Hookeâs law. Such a system is also called a simple harmonic oscillator. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Maximum displacement is the amplitudeXX. The periodTTand frequencyffof a simple harmonic oscillator are given byT=2ÏmkT=2Ïmkandf=12Ïkmf=12Ïkm, wheremmis the mass of the system. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
T=2ÏmkT=2Ïmkandf=12Ïkmf=12Ïkm, wheremmis the mass of the system. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Displacement in simple harmonic motion as a function of time is given byx(t)=Xcos2ÏtT.x(t)=Xcos2ÏtT. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
The velocity is given byv(t)=âvmaxsin2ÏtTv(t)=âvmaxsin2ÏtT, wherevmax=k/mXvmax=k/mX. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
The acceleration is found to bea(t)=âkXmcos2ÏtT.a(t)=âkXmcos2ÏtT. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
A massmmsuspended by a wire of lengthLLis a simple pendulum and undergoes simple harmonic motion for amplitudes less than about15º.15º.The period of a simple pendulum isT=2ÏLg,T=2ÏLg,whereLLis the length of the string andggis the acceleration due to gravity. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
The period of a simple pendulum is | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
whereLLis the length of the string andggis the acceleration due to gravity. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Energy in the simple harmonic oscillator is shared between elastic potential energy and kinetic energy, with the total being constant:12mv2+12kx2=constant.12mv2+12kx2=constant. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Maximum velocity depends on three factors: it is directly proportional to amplitude, it is greater for stiffer systems, and it is smaller for objects that have larger masses:vmax=kmX.vmax=kmX. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
A projection of uniform circular motion undergoes simple harmonic oscillation. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Damped harmonic oscillators have non-conservative forces that dissipate their energy. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Critical damping returns the system to equilibrium as fast as possible without overshooting. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
An underdamped system will oscillate through the equilibrium position. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
An overdamped system moves more slowly toward equilibrium than one that is critically damped. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
A systemâs natural frequency is the frequency at which the system will oscillate if not affected by driving or damping forces. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
A periodic force driving a harmonic oscillator at its natural frequency produces resonance. The system is said to resonate. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
The less damping a system has, the higher the amplitude of the forced oscillations near resonance. The more damping a system has, the broader response it has to varying driving frequencies. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
A wave is a disturbance that moves from the point of creation with a wave velocityvwvw. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
A wave has a wavelengthλλ, which is the distance between adjacent identical parts of the wave. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Wave velocity and wavelength are related to the waveâs frequency and period byvw=λTvw=λTorvw=fλ.vw=fλ. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
A transverse wave has a disturbance perpendicular to its direction of propagation, whereas a longitudinal wave has a disturbance parallel to its direction of propagation. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Superposition is the combination of two waves at the same location. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Constructive interference occurs when two identical waves are superimposed in phase. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Destructive interference occurs when two identical waves are superimposed exactly out of phase. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
A standing wave is one in which two waves superimpose to produce a wave that varies in amplitude but does not propagate. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Nodes are points of no motion in standing waves. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
An antinode is the location of maximum amplitude of a standing wave. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Waves on a string are resonant standing waves with a fundamental frequency and can occur at higher multiples of the fundamental, called overtones or harmonics. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Beats occur when waves of similar frequenciesf1f1andf2f2are superimposed. The resulting amplitude oscillates with a beat frequency given byfB=â£f1âf2â£.fB=â£f1âf2â£. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
Intensity is defined to be the power per unit area: | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
I=PAI=PAand has units ofW/m2W/m2. | https://openstax.org/books/college-physics-2e/pages/16-section-summary |
acoustic impedance : property of medium that makes the propagation of sound waves more difficult | https://openstax.org/books/college-physics-2e/pages/17-glossary |
antinode : point of maximum displacement | https://openstax.org/books/college-physics-2e/pages/17-glossary |
bow wake : V-shaped disturbance created when the wave source moves faster than the wave propagation speed | https://openstax.org/books/college-physics-2e/pages/17-glossary |
Doppler effect : an alteration in the observed frequency of a sound due to motion of either the source or the observer | https://openstax.org/books/college-physics-2e/pages/17-glossary |
Doppler shift : the actual change in frequency due to relative motion of source and observer | https://openstax.org/books/college-physics-2e/pages/17-glossary |
Doppler-shifted ultrasound : a medical technique to detect motion and determine velocity through the Doppler shift of an echo | https://openstax.org/books/college-physics-2e/pages/17-glossary |
fundamental : the lowest-frequency resonance | https://openstax.org/books/college-physics-2e/pages/17-glossary |
harmonics : the term used to refer collectively to the fundamental and its overtones | https://openstax.org/books/college-physics-2e/pages/17-glossary |
hearing : the perception of sound | https://openstax.org/books/college-physics-2e/pages/17-glossary |
infrasound : sounds below 20 Hz | https://openstax.org/books/college-physics-2e/pages/17-glossary |
intensity : the power per unit area carried by a wave | https://openstax.org/books/college-physics-2e/pages/17-glossary |
intensity reflection coefficient : a measure of the ratio of the intensity of the wave reflected off a boundary between two media relative to the intensity of the incident wave | https://openstax.org/books/college-physics-2e/pages/17-glossary |
loudness : the perception of sound intensity | https://openstax.org/books/college-physics-2e/pages/17-glossary |
node : point of zero displacement | https://openstax.org/books/college-physics-2e/pages/17-glossary |
note : basic unit of music with specific names, combined to generate tunes | https://openstax.org/books/college-physics-2e/pages/17-glossary |
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