Physics Flashcards
(239 cards)
1
Q
average velocity
A
V= delta x/ delta t (m/s)
2
Q
force
A
any push or pull that results in an acceleration
3
Q
friction
A
a force that opposes motion as a function of electrostatic interactions at the surfaces of two objects
4
Q
static friction
A
exists between two objects that are not in motion relative to each other; the force that must be overcome to to set an object in motion
5
Q
kinetic friction
A
exists between two objects that are in motion relative to each other; opposes the motion of objects moving relative to each other; fk = μkN
6
Q
acceleration
A
the rate of change of an object’s velocity, a vector quantity
a=delta v/ delta t (m/s^2)
7
Q
Newtons
A
kg ⋅m/s^2
8
Q
Gravitational force
A
Fg= Gm1m2/ r^2
9
Q
Newton’s First Law
A
A body either at rest or in motion with constant velocity will remain that way unless a net force acts upon it. Fnet = ma = 0
10
Q
Newton’s Second Law
A
An object of mass m will accelerate when the vector sum of the forces results in some nonzero resultant force vector. Fnet = ma
11
Q
Newton’s Third Law
A
To every action, there is always an opposed but equal reaction. FAB = -FBA
12
Q
Linear motion equations
A
V= V0 + at X= V0t + 1/2at^2 V^2 = V0^2 + 2ax V = (Vo+V) / 2 X = Vt = (V0+V/2)t
13
Q
Centripetal force
A
Fc = mv^2/r
14
Q
Centripetal acceleration
A
ac=V^2/r
15
Q
Translational equilibrium
A
exists only when the vector sum of all of the forces acting on an object is zero
16
Q
Rotational motion
A
when forces are applied against an object in such a way as to cause the object to rotate around a fixed pivot point, also known as the fulcrum.
17
Q
Torque
A
(moment of force) τ = r × F = rF sin θ
clockwise rotation= negative
18
Q
Rotational equilibrium
A
exists only when the vector sum of all the torques acting on an object is zero.
19
Q
Energy
A
Systems ability to do work, or make something happen
20
Q
Kinetic energy
A
the energy of motion; K= 1/2 mv^2
21
Q
joule
A
kg x m^2/ s^2
22
Q
gravitational potential energy
A
U = mgh
23
Q
elastic potential energy
A
U= 1/2 (kx^2)
24
Q
Total Mechanical Energy
A
E = U + K
25
Work
W = F · d = Fd cos θ; Wnet = ΔK = Kf - Ki
26
Isobaric process
pressure remains constant, W = PΔV
27
Isovolumetric process (isochoric)
volume is constant, no work done
28
Power
P=W/t = ∆E/t
29
Thermal Expansion
ΔL = αLΔT
30
Volume Expansion
ΔV = βVΔT
31
Closed System
capable of exchanging energy, but not matter, with the sur-roundings.
32
Open systems
can exchange both matter and energy with the environment.
33
State Function
thermodynamic properties that are a function of only the current equilibrium state of a system, density, pressure, temperature, volume, enthalpy, internal energy, and entropy
34
Process function
describe the path taken to get from one state to another, work and heat
35
First law of thermodynamics
the change in the total internal energy of a system is equal to the amount of energy transferred in the form of heat to the system, minus the amount of energy transferred from the system in the form of work. ΔU = Q - W
36
Second law of thermodynamics
objects in thermal contact and not in thermal equilibrium will exchange heat energy such that the object with a higher temperature will give off heat energy to the object with a lower temperature until both objects have the same temperature at thermal equilibrium.
37
Conduction
The direct transfer of energy via molecular collisions
38
Convection
The transfer of heat by the physical motion of a fluid
39
Radiation
The transfer of energy by electromagnetic waves
40
Specific heat
q = mcΔT
41
zeroth law of thermodynamics
when one object is in thermal equilibrium with another object, and the second object is in thermal equilibrium with a third object, then the first and third object are also in thermal equilibrium, no net heat will flow between the objects
42
Heat
the transfer of thermal energy from a hotter object with a higher temp to a colder object with a lower temp
43
phase change heat energy
q=mL
44
solidification
liquid to solid
45
fusion
solid to liquid
46
vaporization/evaporation
liquid to gas
47
condensation
gas to liquid
48
Isothermal process
constant temperature, no change in internal energy
49
adiabatic process
no heat exchange
50
entropy
the measure of the spontaneous dispersal of energy at a specific temp: how much energy is spread out, or how widely it is spread out
51
change in entropy
∆S= Qrev/T (J/mol x K)
52
density
p=m/v (kg/ m^3)
53
density of water
1 g/cm^3 = 100 kg/ m^3
54
Fg with known density
Fg = pVg
55
Pressure
P = F/A
| force per area
56
absolute (hydrostatic) pressure
the total pressure that is exerted on an object that is submerged in a fluid
P = P0 + plz
57
gauge pressure
the difference between the absolute pressure inside the tire and the atmospheric pressure outside the tire
P gauge = P - P atm = (Po + paz) - P atm
58
hydrostatics
the study of fluids at rest and the forces and pressures associated with standing fluids
59
Pascal's principle
For fluids that are incompressible—that is, fluids with volumes that cannot be reduced by any significant degree through application of pressure—a change in pressure will be transmitted undiminished to every portion of the fluid and to the walls of the contain-ing vessel.
P = F1/A1 = F2/A2
F2 = F1(A2/A1)
larger area = larger force, but exerted through a smaller distance
60
Buoyancy force
Fbuoy = ρfluid x Vfluid displaced x g = ρfluid x Vsubmerged x g
61
surface tension
results from cohesion
62
cohesion
the attractive force that a molecule of liquid feels toward other molecules of the same liquid
63
adhesion
the attractive force that a molecule of the liquid feels toward the molecules of some other sub-stance.
64
viscosity
resistance of a fluid, more viscous fluids lose more energy flowing
65
laminar flow
smooth and orderly, often modeled as layers of ludicrous that flow parallel to each other, layers closest to the wall of the pipe flows more slowly than the more interior layers of fluid
66
Poiseuille's Law
Q = πr^4x delta P/ 8nL
n = viscosity of fluid, Q = rate of flow
67
Turbulent flow
rough and disorderly, causes the formation of eddies, which are swirls of fluid of varying sizes occurring typically on the downstream side of an obstacle, when fluid exceeds a certain critical speed
68
flow rate
Q = v1A1 = v2A2
| flow more quickly through narrow passages and slowly through wider ones
69
closed loop
non constant flow (the circulatory system)
70
F buoyant
= weight of displaced fluid = P fluid x V object x g
71
photon energy
E = hf
72
Beta decay
a type of radioactive decay in which a beta particle (electron) is emitted from an atomic nucleus
73
Coulomb's law
Fe = kq1q2 / r^2
74
Magnitude of electric field
E = Fe / q = kQ/ r^2
```
q = test charge
Q = source charge
```
75
Electric potential energy
U= kQq/r
76
electric potential
V = U / q = kQ/r
77
potential difference
delta V = Va - Vb= Was/q
78
equipotential line
a line on which the potential at every point is the same. That is, the potential difference between any two points on an equipotential line is zero
79
dipole moment (p)
p = qd (C x m )
80
electric dipole
V = (kqd/r^2) cos theta
81
torque on a dipole
T = pE sintheta
| p=qd
82
tesla (T)
1 T = 1 N x s/ m x C
83
diamagnetic materials
are made of atoms with no unpaired electrons and that have no net magnetic field: wood, plastics, water, glass, and skin
slightly repelled by a magnet
84
paramagnetic materals
have unpaired electrons, so these atoms do have a net magnetic dipole moment; become weakly magnetized in the presence of an external magnetic field, aligning the magnetic dipoles of the material with the external field. Upon removal of the external field, the thermal energy of the individual atoms will cause the individual magnetic dipoles to reorient randomly: aluminum, copper, gold
85
ferromagnetic materals
have unpaired electrons and permanent atomic magnetic dipoles that are normally oriented randomly so that the material has no net magnetic dipole. However, will become strongly magnetized when exposed to a magnetic field or under certain temperatures: iron, nickel, and cobalt
86
magnetic force (Fb)
Fb= qvB sin theta
B = magnitude of magnetic field
any charge moving parallel or antiparallel to the direction of the magnetic field will experience no force from the magnetic field .
87
metallic conductivity
Metal atoms can easily lose one or more of their outer electrons, which are then free to move around in the larger collection of metal atoms. This makes most metals good electrical and thermal conductors.
88
electrolytic conductivity
depends on the strength of the solution
89
current
the flow of charge between two points at different electrical potentials connected by a conductor, such a s a copper wire
I = Q / delta t (the amount of charge Q passing through the conductor per unit time)
1 A = 1 C/s
90
direct current (DC)
in which the charge flows in one direction only
91
alternating current (AC)
in which the flow changes direction periodically
92
electromotive force (emf)
when no charge is moving between the two terminals of a cell that are at different potential values
V = J/C
93
Kirchhoff’s Junction Rule
Iinto junction = Ileaving junction
94
resistance
the opposition within any material to the movement and flow of charge.
R = pL/A
```
p= resistivity ( ohm- meter)
L = length of resistor
A = cross sectional area
```
A longer resistor means that electrons will have to travel a greater distance through a resistant material (if resistor doubles in length. resistance will double)
wider = more current can flow = less resistance
greater resistance at higher temps
95
Ohm's law
V = IR
96
power of the resistor
P = IV = I^2R= V^2 / R
97
resistors in series
current travels through each resistor in order to return to the cell
Vs= V1 + V2 + v3
Rs = R1 + R2 + R3
current stays constant
98
resistors in parallel
electrons have a “choice” regarding which path they will take: some will choose one pathway, while others will choose a different pathway. No matter which path is taken, however, the voltage drop experienced by each division of current is the same because all pathways originate from a common point and end at a common point within the circuit.
Vp = V1 = V2 = V3
Voltage is constant!!!
1/Rp= 1/R1 + 1/R2 + 1/R3
the current in each branch will be inversely proportional to the resistance offered by each branch.
99
capacitors
characterized by their ability to hold charge at a particular voltage.
100
capacitance
C = Q/V (1 F = 1 C/V)
101
micro unit
1 x 10 ^-6
102
pico unit
1 x 10^-12
103
nano unit
1 x 10^-9
104
potential energy stored in a capacitor
U = 1/2 CV^2
105
dielectric material
insulation, increases the capacitance by a factor called the dielectric constant
106
capacitance due to a dielectric material
C′ = κC
C = Aκε0/d
107
ammeters
used to measure the current at some point within a circuit, requires the circuit to be on; inserted in series where the current is being measured and use the magnetic prop-erties of a current-carrying wire to cause a visible needle movement or a calibrated display of the current
108
voltmeters
also use magnetic properties of current-carrying wires. However, are used to measure the voltage drop across two points in a circuit. They are wired in parallel to these two points. Also require circuit to be active
109
Ohmmeters
does not require a circuit to be active, will often have their own battery of known voltage and then function as ammeters through another point in the circuit.
110
sinusoidal waves
may be transverse or longitudinal, the individual particles oscillate back and forth with a displacement that follows a sinusoidal pattern.
111
transverse waves
the direction of particle oscillation is perpendicular to the propagation (movement) of the wave: electromagnetic wave, visible light, microwaves, and X-rays
112
longitudinal waves
ones in which the particles of the wave oscillate parallel to the direction of propagation; that is, the wave particles are oscillating in the direction of energy transfer: sound waves, slinky flat on a table and tapping on end
113
wavelength (λ)
The distance from one maximum (crest) of the wave to the next
114
frequency (f)
the number of wavelengths passing a fixed point per second, and is measured in hertz (Hz) or cycles per second (cps).
115
propagation speed (v)
ν = fλ
116
period (T)
T = 1/f
| the number of seconds per cycle
117
angular frequency (w)
w = 2 pi f = 2 pi /T
118
amplitude (A)
The maximum magnitude of displacement in a wave (from the equilibrium position)
119
principle of superposition
states that when waves interact with each other, the displacement of the resultant wave at any point is the sum of the displacements of the two interacting waves.
120
constructive interference
When the waves are perfectly in phase, the displacements always add together and the amplitude of the resultant is equal to the sum of the amplitudes of the two waves.
121
destructive interference
When waves are perfectly out of phase, the displacements always counteract each other and the amplitude of the resultant wave is the difference between the amplitudes of the interacting waves
122
traveling wave
If a string fixed at one end is moved up and down, a wave will form and travel, or propagate, toward the fixed end. If the free end of the string is continuously moved up and down, there will then be two waves: the original wave moving down the string toward the fixed end and the reflected wave moving away from the fixed end. These waves will then interfere with each other.
123
standing waves
a vibration of a system in which some particular points remain fixed while others between them vibrate with the maximum amplitude.
124
timbre
the quality of the sound, is determined by the natural frequency or frequencies of the object.
125
audible frequencies
between 20 Hz and 20,000 Hz, high-frequency hearing generally declines with age.
126
damping
a decrease in amplitude of a wave caused by an applied or nonconservative force.
127
sound
a longitudinal wave transmitted by the oscillation of particles in a deform-able medium
128
speed of sound
```
v = √B/p
B= a measure of the medium's resistance to compression
p = the density of the medium
```
129
pitch
our perception of the frequency of sound
lower frequency = lower pitch
130
Doppler effect
describes the difference between the actual frequency of a sound and its perceived frequency when the source of the sound and the sound’s detector are moving relative to one another. If the source and detector are moving toward each other, the perceived frequency, f ′, is greater than the actual frequency, f. If the source and detector are moving away from each other, the perceived frequency is less than the actual frequency.
131
Doppler effect equation
f' = f (v ± vD)/ (v ∓ Vs )
top sign for toward
bottom sign for away
```
Vd = speed of detector
Vs= speed of source
```
132
loudness / volume
the way in which we perceive the intensity of a sound
133
sound intensity
the average rate of energy transfer per area across a surface that is perpendicular to the wave. In other words, intensity is the power transported per unit area.
134
Intensity equation
I = P/A
Intensity, therefore, is inversely proportional to the square of the distance from the source.
135
sound level (β)
β = 10 log I/Io
136
wavelength of a standing wave
λ = 2L/ n
n = harmonic
137
frequency of standing wave with n harmonic
f = nv/2L
138
first harmonic (fundamental frequency) (standing wave)
```
n = 1
wavelength = 2L
```
1 antinode
139
second harmonic (standing wave)
```
n = 2
wavelength = L
```
140
third harmonic (standing wave)
```
n = 3
wavelength = 2L/3
```
141
wavelength of closed pipe
λ = 4L/ n
n = 1, 3, 5, etc
142
frequency of closed pipe
f = nv/4L
143
first harmonic closed pipe
```
n = 1
L = λ / 4
```
144
third harmonic closed pipe
L = 3 λ / 4
145
fifth harmonic closed pipe
L = 5 λ /4
146
ultrasound
uses high frequency sound waves outside the range of human hearing to compare the relative densities of tissues in the body, Because the speed of the wave and travel time is known, the machine can generate a graphical representation of borders and edges within the body by calculating the traversed distance
147
doppler ultrasound
used to determine the flow of blood within the body by detecting the frequency shift that is associated with movement toward or away from the receiver.
148
radio waves
long wavelength, low frequency, low energy
149
gamma rays
short wavelength, high frequency, high energy
150
electromagnetic spectrum
microwaves, infrared, visible light, ultraviolet, and XRs
151
electromagnetic waves
are transverse waves because the oscillating electric and magnetic field vectors are perpendicular to the direction of propagation. The electric field and the magnetic field are also perpendicular to each other
152
speed of light (c)
c = fλ
153
visible spectrum
400 nm - 700 nm
154
rectilinear propagation
When light travels through a homogeneous medium, it travels in a straight line
155
reflection
the rebounding of incident light waves at the boundary of a medium. Light waves that are reflected are not absorbed into the second medium; rather, they bounce off of the boundary and travel back through the first medium.
156
real image
if the light actually converges at the position of the image
157
virtual image
if the light only appears to be coming from the position of the image, but does not actually converge there
158
plane mirrors
Parallel incident light rays remain parallel after reflection from a plane mirror; always create virtual images
159
spherical mirrors
concave and convex; have an associated center of curvature (C) and a radius of curvature (r).
160
center of curvature
a point on the optical axis located at a distance equal to the radius of curvature from the vertex of the mirror; in other words, it would be the center of the spherically shaped mirror if it were a complete sphere.
161
converging mirror
the center of curvature and the radius of curvature are located in front of the mirror. (concave)
a ray that strikes the mirror parallel to the axis (the normal passing through the center of the mirror) is reflected back through the focal point. A ray that passes through the focal point before reaching the mirror is reflected back parallel to the axis. A ray that strikes the mirror at the point of intersection with the axis is reflected back with the same angle measured from the normal
Any time an object is at the focal point of a converging mirror, the reflected rays will be parallel, and thus, the image will be at infinity .
focal length is always positive
162
diverging mirror
the center of curvature and the radius of curvature are behind the mirror
forms only a virtual, upright, and reduced image, regard-less of the position of the object. The farther away the object, the smaller the image will be.
focal length is always negative
163
focal length ( f )
the distance between the focal point (F) and the mirror.
| for all spherical mirrors, f=r/2, where the radius of curvature (r) is the distance between C and the mirror
164
o
distance between the object and the mirror
165
(i)
the distance between the image and the mirror
if image distance is positive (i > 0) then it is real and located in front of the mirror
if image distance is negative (i < 0) then it is virtual and located behind the mirror
166
relationship between f, o, I, and r
1/f = 1/o + 1/I = 2/r
167
real image
i > 0
| positive distance, image located in front of mirror
168
virtual image
i < 0
distance is negative
image is behind the mirror
169
magnification
the ratio of the image distance to the object distance
m= −i/o
- means inverted, + means upright
|m| < 1, then reduced image
|m| > 1, then enlarged image
|m|= 1 then image is the same size as the object
170
inverted image
- m
171
upright image
+ m
172
UV NO IR
Upright images are always virtual
No image is formed when the object is a focal length away
Inverted images are always real
173
refraction
the bending of light as it passes from one medium to another and changes speed.
n = c/v
```
c= speed of light in a vacuum
v = speed of light in the medium
n = index of refraction
```
173
refraction
the bending of light as it passes from one medium to another and changes speed.
n = c/v
```
c= speed of light in a vacuum
v = speed of light in the medium
n = index of refraction
```
174
index of refraction
n = c/v
175
Snell's law
n1 sin θ1 = n2 sin θ2
n1 and θ1 refer to the medium from which the light is coming
n2 and θ2 refer to the medium from which the light is entering
when light enters a medium with a higher index of refraction (n2 > n1), it bends toward the normal (sin θ2 < sin θ1; therefore, θ2 < θ1)
if the light travels into a medium where the index of refraction is smaller (n2 < n1), the light will bend away from the normal (sin θ2 > sin θ1; therefore, θ2 > θ1)
176
Total internal reflection
a phenomenon in which all the light incident on a boundary is reflected back into the original material, results with any angle of incidence greater than the critical angle, θc
occurs as the light moves from a medium with a higher refractive index to a medium with a lower one .
177
lenses
refract light
| the light is refracted twice as it passes from air to lens and from lens back to air.
178
convex lens
converging!
179
real image for lenses
on the opposite side of the lens from the original light source
180
virtual image for lenses
on the same side of the lens as the original light source.
181
power of lens
P = 1/f
positive for converging lens, negative for diverging lens
182
concave lens
diverging!
183
nearsighted people need
diverging lens
184
farsighted people need
converging lens
185
Spherical aberration
a blurring of the periphery of an image as a result of inadequate reflection of parallel beams at the edge of a mirror or inadequate refraction of parallel beams at the edge of a lens.
186
Chromatic aberration
a dispersive effect within a spherical lens. Depending on the thickness and curvature of the lens, there may be significant splitting of white light, which results in a rainbow halo around images.
187
diffraction
the spreading out of light as it passes through a narrow opening or around an obstacle.
188
diffraction
the spreading out of light as it passes through a narrow opening or around an obstacle.
189
interference
When waves interact with each other, the displacements of the waves add together
190
XR diffraction
uses the bending of light rays to create a model of molecules. X-ray diffraction is often combined with protein crystallography during protein analysis.
191
Plane-polarized light
light in which the electric fields of all the waves are oriented in the same direction (that is, their electric field vectors are parallel).
192
Unpolarized light
has a random orientation of its electric field vectors; sunlight and light emitted from a light bulb are prime examples.
193
photoelectric effect
When light of a sufficiently high frequency (typically, blue to ultraviolet light) is incident on a metal in a vacuum, the metal atoms emit electrons
194
threshold frequency (fT)
The minimum frequency of light that causes ejection of electrons
195
energy of photon
```
E = hf = hc/ λ
f = frequency of light
```
The energy of a photon increases with increasing frequency
196
maximum kinetic energy of the ejected electron
Kmax = hf - W
196
rig
197
work function
W = hfT
198
fluorescence
If one excites a fluorescent substance (such as a ruby, an emerald, or the phosphors found in fluorescent lights) with ultraviolet radiation, it will begin to glow with visible light. Photons of ultraviolet light have relatively high frequen-cies (short wavelengths). After being excited to a higher energy state by ultraviolet radiation, the electron in the fluorescent substance returns to its original state in two or more steps. By returning in two or more steps, each step involves less energy, so at each step, a photon is emitted with a lower frequency (longer wavelength) than the absorbed ultraviolet photon. If the wavelength of this emitted photon is within the visible range of the electromagnetic spectrum, it will be seen as light of the partic-ular color corresponding to that wavelength.
199
mass defect
the difference between the sum of the masses of nucleons in the nucleus and the mass of the nucleus. results from the conversion of matter to energy
```
E = mc^2
m= mass
c= speed of light
```
200
binding energy
the energy that holds nucleons in the nucleus
| bonded systems is at lower energy than the unbounded constituents
201
atomic number (Z)
corresponds to the number of protons in the nucleus
202
mass number (A)
corresponds to the number of protons plus neutrons
203
fusion
occurs when small nuclei combine to form a larger nucleus
204
fission
a process by which a large nucleus splits into smaller nuclei; through the absorption of a low-energy neutron, fission can be induced in certain nuclei
205
radioactive decay
a naturally occurring spontaneous decay of certain nuclei accompanied by the emission of specific particles.
206
Isotope Decay Arithmetic
When balancing nuclear reactions, the sum of the atomic numbers must be the same on both sides of the equation, and the sum of the mass numbers must be the same on both sides as well.
207
alpha decay
the emission of an α-particle, which is a 4/2He nucleus that consists of two protons, two neutrons, and zero electrons.
very massive compared to a beta particle and carries double the charge
the atomic number of the daughter nucleus will be two less than that of the parent nucleus, and the mass number will be four less.
208
beta decay
the emission of a β-particle, which is an electron and is given the symbol e-or β-, more penetrating than alpha radiation.
a neutron is converted into a proton and a β--particle (Z = -1, A = 0) is emitted. Hence, the atomic number of the daughter nucleus will be one higher than that of the parent nucleus, and the mass number will not change.
209
positron emission
a positron is released, which has the mass of an electron but carries a positive charge. The positron is given the symbol e+ or β+.
a proton is converted into a neutron and a β+-particle (Z = +1, A = 0) is emitted. Hence, the atomic number of the daughter nucleus will be one lower than that of the parent nucleus, and the mass number will not change.
210
gamma decay
the emission of γ-rays, which are high-energy (high-frequency) photons. They carry no charge and simply lower the energy of the parent nucleus without changing the mass number or the atomic number.
211
electron capture
Certain unstable radionuclides are capable of capturing an inner electron that combines with a proton to form a neutron, while releasing a neutrino. The atomic number is now one less than the original but the mass number remains the same; a rare process that is perhaps best thought of as the reverse of β-decay
212
half life
the time it takes for half of the sample to decay. In each subsequent half-life, one-half of the remaining sample decays so that the remaining amount asymptotically approaches zero.
213
exponential decay
n = n0e^-λt
214
13^2
169
215
14^2
196
216
15^2
225
217
16^2
256
218
17^2
189
219
18^2
324
220
19^2
361
221
20^2
400
222
√2
1.4
223
√3
1.7
224
Log 1
= 0
225
Log a A
= 1
226
Log A x B
= log A + log B
227
Log A ^ B
= B log A
228
log 1/A
-log A
229
log 10
= 1
230
log ( n x 10^m)
= m + 0.n
231
sin
opposite / hypotenuse
232
cosine
adjacent / hypotenuse
233
tangent
opposite/ adjacent
234
sin 0 and 180 degrees
= 0
235
cos 0 degrees
= 1
236
tan 0 and 180 degrees
= 0
237
F to C
F = 9/5 C + 32
