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z = z ′ z = z ′
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
t ′ = t − v x / c 2 1 − v 2 / c 2 t ′ = t − v x / c 2 1 − v 2 / c 2
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
x ′ = x − v t 1 − v 2 / c 2 x ′ = x − v t 1 − v 2 / c 2
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
y ′ = y y ′ = y
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
z ′ = z z ′ = z
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
( Δ s ) 2 = ( Δ x ) 2 + ( Δ y ) 2 + ( Δ z ) 2 − c 2 ( Δ t ) 2 ( Δ s ) 2 = ( Δ x ) 2 + ( Δ y ) 2 + ( Δ z ) 2 − c 2 ( Δ t ) 2
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
( Δ τ ) 2 = − ( Δ s ) 2 / c 2 = ( Δ t ) 2 − [ ( Δ x ) 2 + ( Δ y ) 2 + ( Δ z ) 2 ] c 2 ( Δ τ ) 2 = − ( Δ s ) 2 / c 2 = ( Δ t ) 2 − [ ( Δ x ) 2 + ( Δ y ) 2 + ( Δ z ) 2 ] c 2
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
u x = ( u x ′ + v 1 + v u x ′ / c 2 ) , u y = ( u y ′ / γ 1 + v u x ′ / c 2 ) , u z = ( u z ′ / γ 1 + v u x ′ / c 2 ) u x = ( u x ′ + v 1 + v u x ′ / c 2 ) , u y = ( u y ′ / γ 1 + v u x ′ / c 2 ) , u z = ( u z ′ / γ 1 + v u x ′ / c 2 )
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
λ obs = λ s 1 + v c 1 − v c λ obs = λ s 1 + v c 1 − v c
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
f obs = f s 1 − v c 1 + v c f obs = f s 1 − v c 1 + v c
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
p → = γ m u → = m u → 1 − u 2 c 2 p → = γ m u → = m u → 1 − u 2 c 2
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
E = γ m c 2 , where γ = 1 1 − u 2 c 2 E = γ m c 2 , where γ = 1 1 − u 2 c 2
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
K rel = ( γ − 1 ) m c 2 , where γ = 1 1 − u 2 c 2 K rel = ( γ − 1 ) m c 2 , where γ = 1 1 − u 2 c 2
https://openstax.org/books/university-physics-volume-3/pages/5-key-equations
classical (Galilean) velocity addition : method of adding velocities whenv<<c;v<<c;velocities add like regular numbers in one-dimensional motion:u=v+u′,u=v+u′,wherevis the velocity between two observers,uis the velocity of an object relative to one observer, andu′u′is the velocity relative to the other observer
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
event : occurrence in space and time specified by its position and time coordinates (x,y,z,t) measured relative to a frame of reference
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
first postulate of special relativity : laws of physics are the same in all inertial frames of reference
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Galilean relativity : if an observer measures a velocity in one frame of reference, and that frame of reference is moving with a velocity past a second reference frame, an observer in the second frame measures the original velocity as the vector sum of these velocities
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
Galilean transformation : relation between position and time coordinates of the same events as seen in different reference frames, according to classical mechanics
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
inertial frame of reference : reference frame in which a body at rest remains at rest and a body in motion moves at a constant speed in a straight line unless acted on by an outside force
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
length contraction : decrease in observed length of an object from its proper lengthL0L0to lengthLwhen its length is observed in a reference frame where it is traveling at speedv
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
Lorentz transformation : relation between position and time coordinates of the same events as seen in different reference frames, according to the special theory of relativity
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
Michelson-Morley experiment : investigation performed in 1887 that showed that the speed of light in a vacuum is the same in all frames of reference from which it is viewed
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
proper length : L0;L0;the distance between two points measured by an observer who is at rest relative to both of the points; for example, earthbound observers measure proper length when measuring the distance between two points that are stationary relative to Earth
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
proper time : ΔτΔτis the time interval measured by an observer who sees the beginning and end of the process that the time interval measures occur at the same location
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
relativistic kinetic energy : kinetic energy of an object moving at relativistic speeds
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
relativistic momentum : p→,p→,the momentum of an object moving at relativistic velocity;p→=γmu→p→=γmu→
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
relativistic velocity addition : method of adding velocities of an object moving at a relativistic speeds
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rest energy : energy stored in an object at rest:E0=mc2E0=mc2
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rest frame : frame of reference in which the observer is at rest
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rest mass : mass of an object as measured by an observer at rest relative to the object
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second postulate of special relativity : light travels in a vacuum with the same speedcin any direction in all inertial frames
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special theory of relativity : theory that Albert Einstein proposed in 1905 that assumes all the laws of physics have the same form in every inertial frame of reference, and that the speed of light is the same within all inertial frames
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speed of light : ultimate speed limit for any particle having mass
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time dilation : lengthening of the time interval between two events when seen in a moving inertial frame rather than the rest frame of the events (in which the events occur at the same location)
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
total energy : sum of all energies for a particle, including rest energy and kinetic energy, given for a particle of massmand speedubyE=γmc2,E=γmc2,whereγ=11−u2c2γ=11−u2c2
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
world line : path through space-time
https://openstax.org/books/university-physics-volume-3/pages/5-key-terms
Relativity is the study of how observers in different reference frames measure the same event.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Modern relativity is divided into two parts. Special relativity deals with observers in uniform (unaccelerated) motion, whereas general relativity includes accelerated relative motion and gravity. Modern relativity is consistent with all empirical evidence thus far and, in the limit of low velocity and weak gravitation...
https://openstax.org/books/university-physics-volume-3/pages/5-summary
An inertial frame of reference is a reference frame in which a body at rest remains at rest and a body in motion moves at a constant speed in a straight line unless acted upon by an outside force.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Modern relativity is based on Einstein’s two postulates. The first postulate of special relativity is that the laws of physics are the same in all inertial frames of reference. The second postulate of special relativity is that the speed of lightcis the same in all inertial frames of reference, independent of the rel...
https://openstax.org/books/university-physics-volume-3/pages/5-summary
The Michelson-Morley experiment demonstrated that the speed of light in a vacuum is independent of the motion of Earth about the sun.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Two events are defined to be simultaneous if an observer measures them as occurring at the same time (such as by receiving light from the events).
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Two events at locations a distance apart that are simultaneous for an observer at rest in one frame of reference are not necessarily simultaneous for an observer at rest in a different frame of reference.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Two events are defined to be simultaneous if an observer measures them as occurring at the same time. They are not necessarily simultaneous to all observers—simultaneity is not absolute.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Time dilation is the lengthening of the time interval between two events when seen in a moving inertial frame rather than the rest frame of the events (in which the events occur at the same location).
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Observers moving at a relative velocityvdo not measure the same elapsed time between two events. Proper timeΔτΔτis the time measured in the reference frame where the start and end of the time interval occur at the same location. The time intervalΔtΔtmeasured by an observer who sees the frame of events moving at s...
https://openstax.org/books/university-physics-volume-3/pages/5-summary
The premise of the twin paradox is faulty because the traveling twin is accelerating. The journey is not symmetrical for the two twins.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Time dilation is usually negligible at low relative velocities, but it does occur, and it has been verified by experiment.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
The proper time is the shortest measure of any time interval. Any observer who is moving relative to the system being observed measures a time interval longer than the proper time.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
All observers agree upon relative speed.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Distance depends on an observer’s motion. Proper lengthL0L0is the distance between two points measured by an observer who is at rest relative to both of the points.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Length contraction is the decrease in observed length of an object from its proper lengthL0L0to lengthLwhen its length is observed in a reference frame where it is traveling at speedv.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
The proper length is the longest measurement of any length interval. Any observer who is moving relative to the system being observed measures a length shorter than the proper length.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
The Galilean transformation equations describe how, in classical nonrelativistic mechanics, the position, velocity, and accelerations measured in one frame appear in another. Lengths remain unchanged and a single universal time scale is assumed to apply to all inertial frames.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Newton’s laws of mechanics obey the principle of having the same form in all inertial frames under a Galilean transformation, given byx=x′+vt,y=y′,z=z′,t=t′.x=x′+vt,y=y′,z=z′,t=t′.The concept that times and distances are the same in all inertial frames in the Galilean transformation, however, is incon...
https://openstax.org/books/university-physics-volume-3/pages/5-summary
The relativistically correct Lorentz transformation equations areLorentz transformationInverse Lorentz transformationt=t′+vx′/c21−v2/c2t′=t−vx/c21−v2/c2x=x′+vt′1−v2/c2x′=x−vt1−v2/c2y=y′y′=yz=z′z′=zLorentz transformationInverse Lorentz transformationt=t′+vx′/c21−v2/c2t′=t−vx/c21...
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Relativistic phenomena can be explained in terms of the geometrical properties of four-dimensional space-time, in which Lorentz transformations correspond to rotations of axes.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
The Lorentz transformation corresponds to a space-time axis rotation, similar in some ways to a rotation of space axes, but in which the invariant spatial separation is given byΔsΔsrather than distancesΔr,Δr,and that the Lorentz transformation involving the time axis does not preserve perpendicularity of axes or th...
https://openstax.org/books/university-physics-volume-3/pages/5-summary
The analysis of relativistic phenomena in terms of space-time diagrams supports the conclusion that these phenomena result from properties of space and time itself, rather than from the laws of electromagnetism.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
With classical velocity addition, velocities add like regular numbers in one-dimensional motion:u=v+u′,u=v+u′,wherevis the velocity between two observers,uis the velocity of an object relative to one observer, andu′u′is the velocity relative to the other observer.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Velocities cannot add to be greater than the speed of light.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Relativistic velocity addition describes the velocities of an object moving at a relativistic velocity.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
An observer of electromagnetic radiation sees relativistic Doppler effects if the source of the radiation is moving relative to the observer. The wavelength of the radiation is longer (called a red shift) than that emitted by the source when the source moves away from the observer and shorter (called a blue shift) when...
https://openstax.org/books/university-physics-volume-3/pages/5-summary
The law of conservation of momentum is valid for relativistic momentum whenever the net external force is zero. The relativistic momentum isp=γmu,p=γmu,wheremis the rest mass of the object,uis its velocity relative to an observer, and the relativistic factor isγ=11−u2c2.γ=11−u2c2.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
At low velocities, relativistic momentum is equivalent to classical momentum.
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Relativistic momentum approaches infinity asuapproachesc. This implies that an object with mass cannot reach the speed of light.
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The relativistic work-energy theorem isWnet=E−E0=γmc2−mc2=(γ−1)mc2.Wnet=E−E0=γmc2−mc2=(γ−1)mc2.
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Relativistically,Wnet=KrelWnet=KrelwhereKrelKrelis the relativistic kinetic energy.
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An object ofmassmat velocityuhas kinetic energyKrel=(γ−1)mc2,Krel=(γ−1)mc2,whereγ=11−u2c2.γ=11−u2c2.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
At low velocities, relativistic kinetic energy reduces to classical kinetic energy.
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No object with mass can attain the speed of light, because an infinite amount of work and an infinite amount of energy input is required to accelerate a mass to the speed of light.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
Relativistic energy is conserved as long as we define it to include the possibility of mass changing to energy.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
The total energy of a particle with massmtraveling at speeduis defined asE=γmc2,E=γmc2,whereγ=11−u2c2γ=11−u2c2andudenotes the velocity of the particle.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
The rest energy of an object of massmisE0=mc2,E0=mc2,meaning that mass is a form of energy. If energy is stored in an object, its mass increases. Mass can be destroyed to release energy.
https://openstax.org/books/university-physics-volume-3/pages/5-summary
We do not ordinarily notice the increase or decrease in mass of an object because the change in mass is so small for a large increase in energy. The equationE2=(pc)2+(mc2)2E2=(pc)2+(mc2)2relates the relativistic total energyEand the relativistic momentump. At extremely high velocities, the rest energymc2mc2becomes negl...
https://openstax.org/books/university-physics-volume-3/pages/5-summary
λ max T = 2.898 × 10 − 3 m ⋠K λ max T = 2.898 × 10 − 3 m ⋠K
https://openstax.org/books/university-physics-volume-3/pages/6-key-equations
P ( T ) = σ A T 4 P ( T ) = σ A T 4
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h = 6.626 × 10 − 34 J ⋠s = 4.136 × 10 − 15 eV ⋠s h = 6.626 × 10 − 34 J ⋠s = 4.136 × 10 − 15 eV ⋠s
https://openstax.org/books/university-physics-volume-3/pages/6-key-equations
Δ E = h f Δ E = h f
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I ( λ , T ) = 2 π h c 2 λ 5 1 e h c / λ k B T − 1 I ( λ , T ) = 2 π h c 2 λ 5 1 e h c / λ k B T − 1
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K max = e Δ V s K max = e Δ V s
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E f = h f E f = h f
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K max = h f − ϕ K max = h f − ϕ
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f c = ϕ h f c = ϕ h
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E 2 = p 2 c 2 + m 0 2 c 4 E 2 = p 2 c 2 + m 0 2 c 4
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p f = E f c p f = E f c
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E f = h f = h c λ E f = h f = h c λ
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p f = h λ p f = h λ
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p → f = ℏ k → p → f = ℏ k →
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λ c = h m 0 c = 0.00243 nm λ c = h m 0 c = 0.00243 nm
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Δ λ = λ c ( 1 − cos θ ) Δ λ = λ c ( 1 − cos θ )
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1 λ = R H ( 1 2 2 − 1 n 2 ) 1 λ = R H ( 1 2 2 − 1 n 2 )
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1 λ = R H ( 1 n f 2 − 1 n i 2 ) , n i = n f + 1 , n f + 2 , … 1 λ = R H ( 1 n f 2 − 1 n i 2 ) , n i = n f + 1 , n f + 2 , …
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L n = n ℏ , n = 1 , 2 , … L n = n ℏ , n = 1 , 2 , …
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h f = | E n − E m | h f = | E n − E m |
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a 0 = 4 π ε 0 ℏ 2 m e e 2 = 0.529 à a 0 = 4 π ε 0 ℏ 2 m e e 2 = 0.529 Ã
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r n = a 0 n 2 r n = a 0 n 2
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E 0 = 1 8 ε 0 2 m e e 4 h 2 = 13.6 eV E 0 = 1 8 ε 0 2 m e e 4 h 2 = 13.6 eV
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E n = − E 0 1 n 2 E n = − E 0 1 n 2
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E 1 = − E 0 = − 13.6 eV E 1 = − E 0 = − 13.6 eV
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