1
Q
scalars
A
things with only a magnitude
ex. time, distance, speed
2
Q
vectors
A
things with a magnitude and direction
ex. velocity, displacement
3
Q
position vs. time graph
A
- time on x-axis, position on y-axis
- slope = change in position/change in time = average velocity
4
Q
velocity vs. time graph
A
- time on x-axis, velocity on y-axis
- slope = velocity/time = acceleration
- area under curve = displacement
5
Q
free-fall
A
- all objects fall at the same rate (assume no air resistance/friction)
- acceleration = 9.8m/s^2 directed down
6
Q
newton’s 1st law
A
an object at rest/motion will stay at rest/motion unless acted upon by a nonzero net force
7
Q
speed/velocity units
A
m/s
8
Q
acceleration units
A
m/s^2
9
Q
displacement/distance units
A
m
10
Q
force units
A
N, kg*m/s^2
11
Q
inertia
A
- the tendency for an object to remain at rest or in a state of constant velocity
- measured using mass
- objects with more mass have greater inertia
12
Q
mass units
A
kg
13
Q
newton’s 2nd law
A
an object’s acceleration is directly proportional to the net force exerted on it, inversely proportional to the mass, and in the same direction as the net force
14
Q
newton’s 3rd law
A
when one object exerts a force on a second object, the second object exerts a force of equal magnitude and opposite direction on the first object
15
Q
normal force
A
- supports objects resting on surface
- always perpendicular to surface
- at rest, normal force = weight of object
16
Q
tension
A
- the same all along rope
- equal to weight of object for hanging mass at rest
17
Q
resultant vector
A
vector created from tip-to-tail method
18
Q
static friction
A
- force that opposes motion of object at rest
- force must be applied to object for static friction to oppose it
- equal to force applied
- if force applied > maximum force of static friction, the object will move
19
Q
kinetic friction
A
- constant force of friction that opposes motion of object already moving
- less than maximum value of static friction
20
Q
forces on an object on an inclined plane
A
- Fg pointed straight down
- FN perpendicular to surface of plane
- friction parallel to surface opposite of motion
21
Q
projectile motion
A
- object thrown in air only has acceleration in y-axis (g) , constant v for x-axis
- path of projectile is called trajectory, upside down parabola
- at highest point, velocity along y-axis is 0
22
Q
horizontal range
A
- x displacement of projectile when y displacement is 0
- the best angle for maximum range is 45
23
Q
deformation
A
- change in shape of object due to force applied to it
- the larger the force, the larger the deformation
- can be permanent or nonpermanent
24
Q
Hooke’s Law
A
change in length of a solid object is proportional to applied force (F = -kx)
25
spring constant
stiffness of spring, k
26
restoring force
force that brings deformed object back to equilibrium position
27
simple harmonic motion
- occurs when force proportional to displacement pushes object towards equilibrium
- periodic motion repeating in regular intervals
28
period
time it takes for an object to complete 1 oscillation, 1/f
29
frequency
number of oscillations per second, 1/T
30
period unit
seconds
31
frequency unit
1/s, Hz
32
amplitude
max displacement from equilibrium for simple harmonic oscillator
33
amplitude unit
m
34
simple pendulum
- mass suspended from light string, oscillating
- simple harmonic motion when displaced from eq using angle less than 15 degrees
- the only 2 things that affect T are g and L of string
35
uniform circular motion
object moves in circular path at constant speed
36
angle of rotation/angular displacement unit
radian
37
360 degrees
2pi radians
38
angular velocity unit
rad/s
39
centripetal acceleration
- result of constantly changing direction of object in uniform circular motion
- always directed towards center of rotation
40
period for rotational motion
time for 1 full revolution
41
frequency for rotational motion unit
rev/s
42
net centripetal force
net force that causes centripetal acceleration
43
angular acceleration unit
rad/s^2
44
torque for rotational motion
- rotational equivalent to force
- occurs when force is applied at a distance from axis of rotation that causes object to turn/twist
- counterclockwise = positive torque, clockwise = negative torque
45
torque unit
N*m
46
newton's 2nd law of rotational motion
net torque is directly proportional to angular acceleration and inversely proportional to inertia
47
banked curve
- ideal banked curve has no friction
- horizontal component of FN acts as net centripetal force
- there are different ideal banking angles for different velocities
48
fictitious forces
- forces with no physical origin
- appear when system is viewed from accelerating reference frame
ex. centrifugal and coriolis forces
49
centrifugal force
tends to throw an object outward
50
coriolis force
responsible for deflecting winds towards the right in the northern hemisphere and towards the left in the southern hemisphere
51
newton's universal law of gravitation
- all objects attract each other with a force along a line that connects them
- magnitude of force between 2 objects is the same for both objects
- gravitational force between 2 objects is directly proportional to the product of their masses and inversely proportional to their distance squared
52
gravitational field
- vector map of the strength of gravitational force around a mass
- how many newtons of force act per kg of mass (N/kg)
53
weightlessness
- objects in free-fall in frame of reference that is also in free-fall
- gravitational force is still active
54
high tide
water closer to the moon is pulled towards it
55
low tide
occur on side of earth where moon isn't there
55
Kepler's laws
- hold true for basic orbits
- Laws of Elipses, Equal Areas, and Ratios
56
Law of Elipses
orbit of each planet is an elipse with the sun at one focus
57
aphelion
place in orbit where planet is closest to sun
58
perihelion
place in orbit where planet is farthest from sun
59
Law of Equal Areas
- each planet moves so imaginary line drawn from sun to planet sweeps out equal area in equal time
- planets move faster closer to the sun
60
Law of Ratios
ratio of squares of the periods of any 2 planets about the sun is equal to the cubes of their average distances from the sun
61
momentum unit
kg*m/s, N*s
62
momentum
direction of velocity, conserved in system
63
impulse
change in momentum, occurs when force is applied to object for some amount of time
64
newton's second law for momentum
rate of change of momentum is equal to net force applied
65
angular momentum unit
kg*m^2/s
66
law of conservation of angular momentum
if no net torque acts on rotating system, anggular momentum remains constant
67
elastic collision
- objects collide and bounce off each other
- no permanent deformation or energy loss
68
inelastic collision
- objects collide and don't bounce off or stick together
- typically small deformation and energy loss
69
perfectly inelastic collision
- objects collide and stick together
- largest deformation and energy loss
70
work
- force applied to object to cause movement in the direction of the applied force
- positive work when force is in the same direction as motion
- negative work when force is in opposite direction to motion
- zero work when force component and direction are perpendicular
71
work unit
J, N*m
72
power
rate at which work is done
73
power unit
w
74
1 horsepower
746w
75
energy unit
J
76
work-kinetic energy theorem
net work = change in KE
77
potential energy
- energy of position, shape, or configuration
- amount of work it takes to move object from 1 place to another
78
gravitational potential energy
energy stored due to position relative to ground
79
elastic potential energy
energy stored in compressed or stretched string
80
mechanical energy
sum of KE and PE in system
81
law of conservation of energy
in an ideal system with no friction or air resistance, total mechanical energy remains constant
82
simple machines
- used to multiply force
- input work = output work
- ideal simple machines have no loss of energy, nonideal machines lose energy from friction, air resistance, etc.
83
mechanical advantage
- tells you how many times simple machines multiplies force
- ratio of output : input
- unitless
84
pulley mechanical advantage
number of supporting strings
85
complex machines
comprised of 2 or more simple machines
86
efficiency
how much input work is actually converted to output work, 100% for ideal machines
87
waves
- distrubance that propogates from place to place carrying energy, not mass
- particles oscillate back and forth
88
mechanical waves
- require medium to travel through
ex. sound, water
89
electromagnetic waves
- don't require medium to travel through
ex. light
90
transverse waves
- particles carry energy forward and oscillate perpendicular to direction of motion
ex. light, waves on string
91
longitudinal waves
- paricles oscillate parallel to direction of motion
ex. sound waves
92
wave pulse
disturbance where only 1 or a few waves are generated
93
periodic wave
- multiple wave pulses repeating at constant rate for several cycles
- simple harmonic motion
94
crest
highest part of transverse wave, max amplitude
95
trough
lowest part of transverse wave, min amplitude
96
amplitude for waves
distance between midpoint and crest/trough
97
wavelength
distance between 2 identical parts of wave
98
wavelength units
m
99
compressions
part of longitudinal wave with max compression
100
rarefactions
part of longitudinal wave with min compression
101
period for wave
time for 1 wavelength to pass certain position
102
frequency for wave
number of times a wave passes certain position per second
103
superposition
occurs when 2 waves combine and add together to produce resultant wave
104
principle of wave superposition
resultant wave is sum of individual amplitudes
105
constructive interference
crest of waves overlap, larger resultant amplitude
106
destructive interference
crest and trough of waves overlap, smaller resultant amplitude
107
fixed barrier
wave reflects with inverted amplitude
108
loose barrier
wave reflects with the same amplitude
109
wave refraction
- wave enters new medium and changes path of propogation
- for mechanical wave, speed and wavelength change and frequency stays the same
110
standing waves
- oscillate in a fixed location
- constrained between 2 positions, typically fixed ends
- result from interference between incident and reflected waves
111
nodes
points on wave that don't move, destructive interference
112
antinodes
points on wave that move, constructive interference
113
fundamental frequency
- lowest frequency that will create standing wave
- 1st harmonic
- all harmonics that produce standing wave are integer multiples of this
114
sound
- mechanical longitudicnal wave
- the greater the difference between compression and rarefaction, the greater the amplitude
- as wave travels farther from source, amplitude decreases because energy is spread out over a larger distance
115
speed of sound
- how fast sound wave travels in certain medium at certain temperature
- as temp increases, velocity increases
- stiffer material = faster
116
pitch
- low pitch = low f, high pitch = high f
- changing medium doesn't change pitch
117
intensity of sound
- amount of energy passing through given area at given time
- larger amplitude = larger intensity
- sound travels outward spherically, intensity decreases with distance from source
118
intensity unit
w/m^2
119
sound level intensity
- quantity that tells you level of sound relative to threshold of hearing
- doubling loudness of sound increases intensity by 10 and sound level intensity by 10 dB
120
sound level intensity unit
dB
121
doppler effect
- frequency seems higher when source moves closer and lower when source moves away
- for moving source and stationary observer, use + when source moves away and - when it moves closer
- frequency seems higher when approaching source and lower when moving away from source
- for moving observer and stationary source, use + when approaching and - when moving away
122
beats
- result of 2 sound waves that interfere with each other
- beat frequency
123
damping
- energy lost from system undergoing simple harmonic motion bc of friction and air resistance
- critical, under, over
124
critical damping
oscillator returns as quickly as possible to eq
125
under damping
oscillator slowly decreases oscillations
126
over damping
oscillator takes a long time to return to eq
127
driving
- energy added into system to keep it oscillating at certain frequency
- when system is driven at natural frequency, it enters resonance and its amplitude becomes larger
128
natural frequency
frequency a system vibrates at without damping/driving
129
standing sound waves
result of resonance of sound wave traveling in open or closed pipe
130
closed end pipe
- node at closed end, antinode at open end
- only odd harmonics
131
open end pipe
- antinode at both ends
- even and odd harmonics
132
visible light spectrum
400-750 nm
133
violet light
400 nm
134
red light
750 nm
135
additive primary colors
- red, green, blue
- all 3 = white
136
subtractive primary colors
- cyan, magenta, yellow
- all 3 = black
137
color blindness
occurs when light sensitive cells in eyes fail to appropriately respond to variations in wavelength
138
speed of light
all electromagnetic waves in vacuum travel at the same speed, they slow down in mediums
139
illuminance
intensity of light on surface
140
illuminance unit
lx
141
reflection of light
- occurs any time wave encounters boundary between 2 mediums
- typically reflects back in different direction
141
polarized light
- light only vibrates in 1 direction, the direction of the electric field
- first pass through polarier halves intensity, following passes have decreased intensity according to law of malus
142
incident ray
travels from source to surface
143
reflected ray
reflected off surface
144
angles of incidence and reflection
always equal according to law of reflection
145
specular reflection
light rays reflect off smooth surface
146
diffuse reflection
light rays reflect off rough surface
147
mirror
surface that's good at reflecting light
148
plane mirror
flat, real, unmagnified, reversed image
149
virtual images
formed by light rays that don't converge at location of image
150
concave mirror
- reflecting surface is curved inward
- positive focal point
151
convex mirror
- reflecting surface caved outward
- negative focal point
- always virtual image
152
center of curvature
2x the focal point
153
focal point
halfway between center of curvature and mirror
154
magnification
- ratio of height of image to height of object
- m>1 = bigger image, m<1 = smaller image
- m = upright, -m = inverted
155
index refraction (n)
depends on medium
156
refraction of light
- bending of wave that enters a medium where speed is different
- traveling from lower n to greater n bends light towards normal line
157
Snell's law
relates n of 2 mediums to angles light bends relative to normal line to surface
158
total internal reflection
happens when ray of light travels from higher n to lower n
159
critical angle
angle that total internal reflection occurs at
160
lens
thin piece of glass with curved surface that uses refraction to focus light
161
converging lens (double convex)
- thicker in middle
- positive focal point
162
diverging lens (double concave)
- thicker around edges
- negative focal point
- always virtual image
163
optical power
degree to which lens converges or diverges light
164
focal point ray
travels from top of object through focal point and reflects parallel to primary axis
165
parallel ray
travels from top of object parallel to primary axis and reflects through focal point
166
primary axis ray
travels from top of object to point where primary axis intersects with mirror and reflects back at the same angle
167
real image
rays intersect in front of the mirror
168
virtual image
rays intersect behind mirror
169
3 rays for convex lens
- parallel: top of object to lens, refracts through f on other side
- focal point: top of object through f on same side, refracts parallel
- midpoint: directly through center of lens
170
3 rays for concave lens
- parallel: parallel to primary axis, emerges from f
- focal point: travels towards f on other side and refracts parallel
- midpoint: through midpoint
171
electric charge
- property of object that allows it to be attracted or repelled from another object
- like charges repel and opposites attract
- most objects have neutral charge
172
static electricity
buildup of electric charge on surface of object
173
charge unit
C
174
elementary charge
1 quantity of charge is an integer multiple of elementary charge (quantization)
175
law of conservation of charge
- charge can't be created or destroyed, only transferred between objects
- total amount of charge in any process is constant
176
charging by friction/triboelectric charging
- one object rubs against another one and leaves one charged positively and one negatively
177
insulators
- materials that charges can't move in
ex. wood, rubber, plastic, vinyl
178
conductors
- materials charges can move in
ex. metal
179
semi conductor
- materials that can be insulators or conductors depending on environment
ex. silicon, germanium
180
charging by conduction/contact
charged conductor comes in contact with neutral conductor
181
charging by induction
- induces charge without contact
- charged object brought near neutral conductor polarizes conductor, charges separate but objects remain neutral
- through polarization, charged object can become attracted to neutral object
- conductor receives charge opposite to the one used to charge it
182
grounding
provides path for excess charge to flow out of conductor
183
electrostatic force
force of attraction/repulsion between 2 charged objects
184
Coulomb's law
electrostatic force is directly proportional to product of 2 charges and inversel proportional to distance squared
185
force fields
map of strength and direction of force that acts at a distance around object causing force
186
electric field
- 3 dimensional map of strength and direction of electrostatic force acting upon point charge some distance from charged object
- point charge is usually positive
- strength of electrostatic force at location per C of charge
- strength of electric field is independent of positive test charge used to measure strength
187
electric field lines
- always begin on + charge and end on - charge
- number of field lines is proportional to magnitude of charge
- density of lines is proportional to strength of field
- field lines can never cross
188
electric potential
amount of work/energy needed per unit of electric charge to move the charge from a reference point to a specific point (voltage)
189
electric potential difference
difference in electric potentials within field at 2 different positions
190
net electric potential
in system with multiple point charges, add up potentials at each position
191
electric field unit
V/m, N/C
192
electric current
- rate at which charge flows
- flows from high potential to low
- voltage needed for flow
193
conventional current
flow of positive charges from positive terminal of bettery to negative
194
electron current
flow of negative charges within wire
195
electric current unit
C/s, A
196
resistors
electric devices that slow flow of charge
197
resistance
depends on material, length, and area
198
resistance unit
Ω
199
Ohm's Law
current through wire is directly proportional to V and inversely proportional to R
200
simple circuit
- resistors connected by wires to voltage source
- voltage across each resistor equals voltage of voltage source
201
direct current
- current flowing in 1 direction
- constant V
202
alternating current
current oscillates back and forth
203
resistors connected in series
- connected in straight line
- current through each one is same as total current in circuit
- voltage in each one adds to total voltage in circuit
- equivalent resistance = sum of all resistors
204
resistors connected in parallel
- connected to provide multiple paths for current to flow
- current across each branch adds to equal total current
- voltage is the same in each resistor
- equivalent resistance is always less than 1 resistor
205
electrical power
rate at which electrical energy is supplied by source is dissipated by resistor
206
electrical energy unit
Kwh
207
1 kwh
3.6E6 J
208
bar magnets
- 2 poles, N and S
- if magnet is cut in half, each half will have 2 poles
- like poles repel, opposites attract
209
magnetic field
describes strength of magnetic force in space around magnet
210
magnetic field lines
- continuous loops that point from north to south pole
- stronger and closer together at poles
- fields can store energy
211
magnetic field units
T, G
212
1 G
10^-4 T
213
earth magnetic field
- poles are opposite geographic poles
- B = 5E-5 T
214
permanent magnets
- electrons orbiting and spinning
- ferromagnetic materials
- when electrons all spin in the same direction, large field is produced
- when they spin in opposite directions, fields cancel out
215
magnetic domains
- groupings of atoms with electron spins in the same direction
- each grouping acts as a small magnet
- when domains align there's a strong field
216
current-carrying wire
produces magnetic field around it in circular loops
217
1st right hand rule
- thumb = direction of current
- fingers curl in direction of B field
218
solenoid
- long wire spun in closely wound loops
- strong, uniform B field inside
- strength proportional to number of loops and current that passes through
219
magnetic force
- no magnetic force on stationary charge
- max force when particle moves perpendicular to B-field
220
2nd right hand rule
- index finger: direction of velocity/current
- middle finger: B-field
- thumb: magnetic force if charge is positive, if charge is negative it's in the opposite direction
221
a particle will travel in a circle when
the V is perpendicular to the B-Field
222
magnetic torque
current-carrying loop placed in B field experiences torque that causes it to rotate
223
electric motor
- current carrying loop in B-field rotating because of torque
- convert electric energy to mechanical
224
induced current/emf
- changing magnetic field passing through coil of wire induces electric current in the coil
- primary coil must induce voltage in secondary coil
- induced current depends on voltage and resistance of coil
225
magnetic flux
- measure of B-field lines passing through area
- max flux when angle between area vector normal to loop and B-field is 0
226
magnetic flux unit
Tm^2, Wb
227
Faraday's law of induction
induced voltage is directly proportional to number of turns in coil and rate of change of magnetic flux passing through
228
Lenz's law
- induced current always flows in direction that opposes changing b-field
- induced current produces induced b-field that opposes changing flux through loop
- rhr 1: thumb in direction of induced b-field and fingers curl in direction of current
- objects that move in B-field can experience induced current and emf
229
electric generators
- convert mechanical energy into electrical energy
- mechanical energy rotates coil through B-field to produce motional emf inside coil
- can produce alternating or constant emf
230
electric transformer
- allows you to increase or decrease vltage when connected to AC circuit
- power of primary coil = power of secondary coil
231
step up transformers
- increase V
- have secondary coil with more turns than primary
- decreases I in secondary
232
step down transformer
- decrease V
- have secondary coil with less turns than primary
- increases I in secondary
233
fluids
- substances that can flow
- individual molecules can move
- no fixed shape
- liquids and gases
234
gases
- expand to fill container
- compressible
234
liquids
- maintain volume
- incompressible fluid
- constant density
234
density units
g/ML, g/cm^3, kg/m^3
234
mass vs. volume graph
slope is density
235
average density
total density of system
235
floating objects
have less density than fluid
236
submerged objects
displace fluid equal to its volume
237
pressure
- magnitude of perpendicular force per unit area exerted over surface area
- force from fluid pressure always acts perpendicular to any solid surface it's in contact with
- pressure on object increases linearly with depth in fluid
238
pressure units
N/m^2, Pa
239
1 atm
101300 Pa
240
guage pressure
pressure measured relative to atmospheric pressure
241
absolute pressure
sum of guage pressure and atm pressure
242
Pascal's principle
- if external pressure is applied to confined fluid, pressure at every point in the fluid increases by that amount
- total pressure is sum of all pressures from different sources
- hydraulic press
243
hydraulic press
- apply pascal's principle
- 2 different sized pistons enclosing incompressible fluid
- pressure applied to 1 piston increases pressure in entire system and causes 2nd piston to move
244
buoyant force
- imbalance of forces related to different pressures exerted on submerged object
- upward force exerted on object by fluid
- object at rest has B force equal to weight
- if FB>Fg, object accelerates up, if Fg>FB, object sinks
245
Archimedes's principle
- buoyant force on object equals the weight of displaced fluid
- object will float if ratio of its density to fluid density is less than one
- if volume submerged < total volume, it floats
246
cohesion
attractive forces between molecules of the same substance
247
adhesion
attractive forces between molecules of different substances
248
surface tension
- tendency of liquid's surface to contract and minimize surface area due to cohesion
- if adhesion > cohesion, concave up meniscus (ex. water) if cohesion > adhesion, concave down meniscus (ex. mercury)
249
capillary action
movement of liquid up and down narrow tube because of cohesion and adhesion
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