Physics Flashcards
1
Q
Vector
A
numbers that have direction and magnitude
Ex/ displacement, velocity, acceleration, force, weight
2
Q
Scaler
A
numbers that have magnitude
Ex/ distance, speed, energy, pressure, mass, work
3
Q
Dot product
A
the product of multiplying 2 vectors and the cosine of the angle between them to produce a scaler
A·B = |A| |B| cos 𝜃
4
Q
Cross product
A
the product of multiplying 2 vectors and the sin of the angle between them to produce another vector
A x B = |A| |B| sin 𝜃
5
Q
Velocity
A
Instantaneous speed of an object is equal to the magnitude of the objects instantaneous velocity (v) vector
v = Δx/Δt
6
Q
Gravitational force
A
all objects exert gravitational forces on each other
Fg = Gm1m2 / r²
7
Q
Newton’s first law
A
an object at rest, or in motion at constant velocity, will remain so until a force acts on it
8
Q
Newton’s second law
A
F(net) = ma
9
Q
Newton’s third law
A
- every force exerted by object A on object B, will result in a force by object B on object A
- F = -F
- For every reaction, there is an equal and opposite reaction
10
Q
Kinematics equations
A
v = v₀ + at x = v₀t + 1/2at² —> x = v₀t + at² / 2 v² = v₀² + 2aΔx
11
Q
Terminal velocity
A
When the drag force equals the magnitude of the weight of an object (object is falling at constant velocity). The force of gravity and air resistance are equal
12
Q
Projectile motion
A
Force and acceleration in the vertical direction only. Distance can only be found with the horizontal components of the force
13
Q
Incline planes
A
Fg (parallel) = mg sin 𝜃
Fg (perpendicular) = mg cos 𝜃
14
Q
Normal force
A
equal in magnitude to the perpendicular component of gravity
15
Q
Centripetal force
A
Fc = mv^2 / r
16
Q
Centripetal acceleration
A
Ac = v^2 / r
17
Q
Torque
A
Application of a force at some distance from the fulcrum
𝞃 = F x r = F x r (sin𝜃)
- 𝜃 is the angle between the lever arm and force vectors
18
Q
Kinetic energy
A
KE = 1/2 mv²
19
Q
Gravitational potential energy
A
U = mgh
20
Q
Elastic potential energy
A
U = 1/2 kx²
When k is not given, F = |kx| —> k = F/x
21
Q
Total mechanical energy
A
E = U + K
If there is an increase in 1, there is a decrease in the other
22
Q
Conservative forces
A
Forces, like gravitational and electrostatic, that do not disrupt the flow of energy
23
Q
Nonconservative forces
A
Forces like friction, air resistance, viscosity, and convection that do disrupt the flow
24
Q
Work
A
Transfer of energy from one system to another
W = Fd = Fd x cosϴ
F = W / d —> F = KE / d
25
Isobaric process
When pressure of the system is constant and volume changes. This does not effect the 1st law
W = P∆V ( J = N/m² x m³)
26
Power
The rate at which energy is transferred. Unites in Watt (W) or J/s
P = W/t
P = ∆E/t (energy/time)
P = KE/t
27
Work-energy theorem
W = ∆KE = KEf - KEi
28
Mechanical advantage
MA = (force exerted on object by machine) / (force exerted on machine)
29
Efficiency
Efficiency = (load x load distance) / (effort x effort distance)
- Load is the weight and effort is the force
30
0th law of thermodynamics
If object A is in thermal equilibrium with object B, and object B is in thermal equilibrium with object C, then object A and object C are in thermal equilibrium. No net heat will flow between these objects
31
Heat
Transfer of thermal energy from a object with higher temp to one with lower
32
Thermal equillibrium
When no net heat flows between objects
33
Absolute zero
The lowest temperature possible where no heat is produced from the movement of particles. A substance at absolute zero displays no kinetic energy
34
Fahrenheit, Celsius, and Kelvin conversion
```
F = 9/5 C + 32
K = C + 273
```
35
Linear thermal expansion
∆L = ⱭL∆T
36
Volumetric thermal expansion
∆V = βV∆T
37
Isolated system
No exchange of energy or matter with the surroundings
38
Closed system
Exchange of energy, but not matter
39
Open system
Exchange of energy and matter
40
Calorie to joule conversion
1 Cal = 1000 cal (1 kcal) = 4184 J
41
Conduction
Direct transfer of energy through molecular collisions
42
Convection
Transfer of heat by the physical motion of fluid over a material. Only liquids and gasses exhibit this
43
Radiation
Transfer of energy through electromagnetic waves. This can be transferred in a vacuum
44
Specific heat
Relationship between adding/removing heat energy to a system and how much the temperature changes based on how much energy is added or removed.
q = mc∆T
45
Specific heat of water
1 cal/g·℃ or 4.184 J/g·K
46
Specific heat during a phase change
q = mL where L is the heat of fusion or vaporization
47
Heat of fusion
Heat of transformation at the melting point
48
Heat of vaporization
Heat of transformation at the boiling point
49
Isothermal process
When the system's temperature is held constant so ∆U = 0 and Q = W
50
Adiabatic process
When there is no heat exchange between the system and surroundings so Q = 0 and ∆U = -W
51
Isovolumetric process
When there is no change in volume and no work is done in the process so W = 0 and ∆U = Q
52
Entropy
Measure of spontaneous dispersal of energy at a specific temp
∆S = Q (rev) / T
53
1st law of thermodynamics
Conservation of energy: Energy is not created or destroyed, just transferred from one form to another. Any change in the total energy of the system is due to work or heat
∆U = q - W or ∆U = q + W (if energy is being transferred out of the system)
54
2nd law of thermodynamics
Entropy always increases over time
| ∆S universe = ∆S system + ∆S surroundings > 0
55
3rd law of thermodynamics
Absolute zero temperature is unattainable
56
Density
ρ = m / V
| Units: kg/m³ or g/mL —> g/cm³
57
Density of water
1 g/cm³ —> 1000 kg/m³
58
Specific gravity
The density of a substance compared to the density of water. Finding the difference in densities of a substance and water gives you the ability to find the density of the other solutes (excluding the substance and water)
SG = ρ / 1 g/cm³ or 1 g/mL
59
Pressure (fluids)
P = F/A
| 1 Pa = 1 N/m²
60
Pascal to atmosphere conversion
1.013 x 10⁵ Pa = 100 kPa = 760 mmHg = 760 torr = 1 atm
61
Absolute pressure
Also known as hydrostatic pressure
P = Po + ρgz
z = depth
Po = 10⁵ Pa
62
Gauge pressure
Pressure in a closed space above atmospheric pressure
| Pgauge = P - Patm = (Po + ρgz) - Patm
63
Pascal's prinicple
In a incompressible fluid, a change in pressure will be transmitted to each portion of the fluid and to the walls of the vessel
64
Archimede's principle
When a object is wholly or partially immersed in a fluid, it will be buoyed upward by a force equal to the weight of the fluid that is displaced
Fbuoy = ρ(fluid) x V(fluid displaced) x g = ρ(fluid) x V(submerged) x g
65
Buyount force
Exerted by the mass of a fluid that is displaced (corresponds to the volume of fluid displaced). It always directed upward
Fbuoy = mg = ρVg
66
% of an object submerged
(ρ(object) / ρ(fluid)) x 100
67
Surface tension
Causes liquids to form a strong layer at the surface due to the increased intermolecular attraction
68
Cohesion
Attractive force that a molecule of liquid feels towards molecules of the same liquid. It leads to a net upward force
69
Adhesion
Attractive force that a molecule of liquid feels towards molecules of an other substance
70
Poiseuille’s Law
Q = 𝛑r⁴ΔP / 8𝛈L
*Assume laminar flow. In laminar flow, the center of the “pipe” moves fastest while the “edges” have no velocity due to the no-slip boundary
71
Continuity equation
Q = A₁v₁ = A₂v₂
| Volume flow rate = Q = A1v1
72
Bernoulli’s equation
More energy dedicated to fluid movement means less energy dedicated to static fluid pressure
P₁ + 1/2ρv₁² + ρgh₁ = P₂ + 1/2ρv₂² + ρgh₂
73
Dynamic pressure
1/2ρv²
74
Static pressure
P + ρgh
75
Venturi effect
In a dumbbell shaped tube, point A has the larger radius and B is smaller. Going from A to B, the area decreases, but v increases. So as a fluid is flowing through, the dynamic pressure increases and the static pressure decreases. If a column of fluid is sticking up at A and B, the absolute pressure in B will be lower than A
76
Fainting
Occurs after there is insufficient blood flow to the brain. According to the equation P=pgz, decreases in height (or increase in depth) —> increase in pressure. So when blood flow is insufficient, you faint in order to decrease the height your brain is at so there can be an increase in pressure (more blood flow to brain)
77
Faraday's constant
96,485 C/mol or 10⁵ C/mol
78
Coulomb's law
Describes the electrostatic force between 2 charges
| Fc = kq₁q₂ / r²
79
Test charge
q, the force place in the field
80
Source charge
Q, the force exerted by the field
81
Electric field lines
Drawn away from positive sources are towards negative sources. If the magnitude of the charge increases or decreases, the density (number of lines) of the lines increase or decreases
82
Electrical potential energy
A form of potential energy that is dependent on the relative position of a charge with respect to another charge
U = kQq / r²
U = qEd or U = qV
U = 1/2 CV²
83
Electric potential
The ratio of a charge’s electric potential energy to the magnitude of the charge itself
V = U/q or U = ΔVq
V is the electrical potential measured in Volts = 1 J/C
84
Dipole moment
p, the product of charge and separation distance. It is a vector that points from the (+) to (-) charge along d
p = qd
85
Diamagnetic materials
made up of unpaired electrons that have no net magnetic field. Ex/ wood, plastic
86
Paramagnetic materials
become weakly magnetized in the presence of a magnetic field. Ex/ Al, Au, Cu
87
Ferromagnetic materials
strongly magnetized in the presence of a magnetic field. Ex/ Fe, Ni, Co
88
Current
Amount of charge passing through a conductor per unit time
I = Q/Δt
1 A = 1 C/s
89
Potential difference
It is the voltage or the difference in potentials required for a current to flow
90
Electromotive force (emf)
the “pressure” or “force” that causes a current to move when there is a potential difference
91
Galvanic (voltaic) cell
Electrochemical cell that contains spontaneous oxidation-reduction reactions that generate emf as a result of the differences in reduction potentials of 2 electrodes and a salt bridge to prevent charge buildup
92
Junction rule
the sum of currents flowing into a point (or junction) must equal the sum of the currents flowing away from that point
93
Loop rule
in a closed circuit, the sum of the voltage that is used will always equal the sum of the voltage that is lost (dropped)
94
Resistance
the opposition of flow of charge
| R = ρL / A
95
Ohm's law
V = IR measured in Ω. Voltage and current are directly proportional when R is constant
96
Power
When energy is produced by a flow of electrons, electrical potential energy is converted to kinetic energy driven by the emf
P = W/t or P = ΔE/t
P = IV —> P = I²R or P = V²/R
97
Resistors in series
```
V𝗌 = V₁+V₂+V₃ +…
R𝑠 = R₁+R₂+R₃+…
```
98
Resistors in parallel
```
V𝗉 = V₁=V₂=V₃=…
1/R𝗉 = 1/R₁+1/R₂+1/R₃…
```
99
Capacitor
has the ability to hold charge at a particular voltage (Ex/ defibrillator)
100
Capacitance
the ratio of the charge stored on 1 plate to the voltage across the whole capacitor
C = Q/V
C = 𝞮₀ (A/d)
Units in Farad. 1F = 1 C/V
101
Uniform electric field
Creates a separation of charges
| E = V/d
102
Dielectric material
An insulator. When a insulator is introduced between the plates of a capacitor, the capacitance increases by a factor called the dielectric constant (𝜅).
103
Capacitors in series and parallel
```
1/C𝑠 = 1/C₁+1/C₂+1/C₃+…
C𝗉 = C₁+C₂+C₃+…
```
104
Wave speed
v = fλ —> f = v/λ -> f = c/λ
105
Wave period
T = 1/f —> f = 1/T
f is in units of cycles/sec or Hz
106
Range of human ear
Frequencies between 20 and 20,000 Hz
107
Ultrasonic waves
Frequencies higher than normal human hearing (>20 kHz)
108
Damping
Also called attenuation. Causes a decrease in the amplitude (an interruption) due to a nonconservative force
109
Sound wave speed
Sound waves are longitudinal waves that can only be transmitted through a medium (speed through a medium: gas < liquid < solid)
v = √B/𝜌
110
Doppler effect
fo = f𝘴 (v±vo / v∓v𝘴)
The upper sign is used if the detector or source is moving toward the object
The lower sign is used if the detector or source is moving away from the object
111
Intensity
I = Power/Area in W/m²
*I = 2π²𝒑𝒇²A²𝐯
112
Threshold of hearing (I₀)
1 x 10⁻¹² W/m² or 0 dB
113
Sound level
β = 10 log I(final)/I₀
| measured in decibels (dB)
114
Visible light spectrum
700nm - 400nm (red —> purple)
115
Electromagnetic spectrum
Radio-->micro-->IR-->visible light-->UV-->X-ray-->Gamma
116
Speed of light
The speed of light (c) is 3 x 10⁸ m/s
| c = λf
117
Optics (mirror/lens) equation
1/f = 1/o + 1/i = 2/r
118
Magnification
m = - i/o
If |m| <1 then the image is smaller than the object (reduced)
If |m| >1 then the image is larger than the object (enlarged)
119
Converging mirrors
Positive focal length (positive power)
- Behind focal point - real, inverted, magnified
- On focal point - no image
- Front focal point - virtual, upright, magnified
120
Diverging optics
Negative focal length (negative power)
| - Object only forms virtual, upright, reduced images (Ex/ parking garage mirrors).
121
Snell's law
n = c/v --> n₁sinθ₁ = n₂sinθ₂
- n = index of refraction (refraction is due to wavelength)
- v is the speed in the medium (gas > liquid > solid)
- n and v have an inverse relationship
- 1 is where light is coming from and 2 is where it is entering
122
Power (optics)
```
p = 1/f
Power is (+) for converging lens and (-) for diverging lens
```
123
Hyperoptia
farsightedness
124
Myopia
nearsightedness
125
Spherical aberration
Occurs when there is blurring of the periphery of an image
| and is the result of inadequate reflection or refraction of parallel beams
126
Plane polarized light
Light is polarized when the electric and magnetic fields are oriented in a particular (not random) way. It exhibits a particular alignment, separation, or orientation
127
Florescence
emission of light after the absorption of light
128
Chromatic aberration
occurs when there is a splitting of white light due to the thickness and curvature of a lens that results in rainbow halos around images
129
Diffraction
process by which a beam of light or other system of waves is spread out as a result of passing through a narrow aperture or opening
130
Dispersion
occurs when various wavelengths of light separate from each other after traveling through a medium
131
Refraction
The bending of light as it moves from one medium to another changing the speed. This has to do based on wavelength (not frequency)
132
Threshold frequency
fT, the minimum amount of light (photons) that causes ejection of electrons from a metal
where the energy of each photon is E= hf
133
Plank's constant
f = Plank’s constant = 6.6 x 10⁻³⁴ J·s
134
Mass defect
the difference between the sum of all individual nucleons (protons and neutrons) in a nucleus and the actual mass of the nucleus
E = mc²
135
Binding energy
energy that holds the nucleons together at the low energy level. The difference of energy is radiated away (heat, light, radiation)
136
Isotopic notation
ᴬzX where A is the mass number (protons+neutrons) and Z is the atomic number (# of protons)
137
Fusion
occurs when small nuclei combine to form a larger nucleus
138
Fission
occurs when a large nucleus splits into smaller nuclei
139
Radioactive decay
ᴬzX —> ᴬzY + decayed particle where X is the parent nucleus and Y is the daughter nucleus. It is a function of isotopes
140
Alpha decay
The emission of an α-particle (⁴₂He). The daughter nucleus will have 2 less protons than the parent. The mass number will be 4 less
141
Beta decay
The breakdown of a neutron into a proton and electron and the emission of a newly created electron (⁰-₁e⁻). The mass number stays the same, but the atomic number increases by 1
142
Positron emission
The emission of a positron (⁰-₁β⁺) when a proton becomes a neutron. This is a type of β decay. A positron can be thought of as an electron with a positive charge (⁰₁e⁻). The mass number will stay the same, but the atomic number will decrease by 1
143
Gamma decay
Also called gamma ray emission, occurs when an electron and positron collide. It accompanies other types of radioactive decay and does not change the identity of atom from which it is given off
⁰₁e⁻ + ⁰-₁e⁻ -> ⁰₀𝛾 + ⁰₀𝛾
144
Electron capture
The capture of an electron (⁰-₁e⁻) and the merging of that electron w/ a proton to create a neutron. The mass number of the product stays the same, but the atomic number will decrease by 1. Emission of 𝛾-rays (⁰₀𝛾), which are high frequency photons, occurs also
145
Half life
The time it takes for half the sample to decay. All atoms other than hydrogen are subject to some type of spontaneous decay.
(1/2)ˣ = y where x = the # of half lives and y = the amount of sample left after time has passed
146
Exponential decay
Describes how the number of radioactive nuclei changes with time
147
Variables of half life problems
1) initial amount of substance 2) final amount of substance 3) length of half life 4) the number of half lives
148
Axis of phase change diagram
Energy on the X axis and temperature on the Y axis
149
Translational equilibrium
An object is in translational equilibrium when the sum of all the external forces acting on the object equals zero
150
Force (electric field)
F = qE
151
Photoelectric effect
When photons strike metal and cause the ejection of electrons
152
Wavenumber
The inverse of wavelength (λ)
153
Rigidity
Inversely proportional to the delocalization of e- meaning if a double bond has more resonance structures, it is less rigid. Ex/ ethene is more rigid than ozone
154
Right hand rule
Point your thumb in the direction of the current and wrap your fingers around the current carrying wire. Your fingers represent the circular field lines, curling around the wire.
155
Internal resistance
If internal resistance is non-negligible, then the emf of the circuit must be greater than the voltage applied.
V = emf - i·r(internal)
156
Resonance
When the natural frequency and the driving force are equal
157
To resonate
vibrate
158
Heat capacity
C = mc -> q = CΔT = mcΔT
