absolute pressure—the total pressure of a fluid at the bottom of a column; equal to the pressure acting on the top of the column plus the pressure caused by the fluid in the column
acceleration—the change in an object’s velocity divided by the time it took to make that change; equal to the derivative (slope) of an object’s velocity–time function
adiabatic process—a process during which no heat flows into or out of the system
alpha particle—two protons and two neutrons stuck together
amplitude—the maximum displacement from the equilibrium position during a cycle of periodic motion; also, the height of a wave
angular momentum—the amount of effort it would take to make a rotating object stop spinning
antineutrino—a subatomic particle; see “neutrino”
antinode—point on a standing wave where the wave oscillates with maximum amplitude
Archimedes’ principle—the buoyant force on an object is equal to the weight of the fluid displaced by that object
atom—the fundamental unit of matter; includes protons and neutrons in a small nucleus, surrounded by electrons
atomic mass unit (amu)—the mass of a proton; also the mass of a neutron
atomic number—the number of protons in an atom’s nucleus
average speed—the distance an object travels divided by the time it took to travel that distance (see “speed”)
beats—rhythmic interference that occurs when two notes of unequal but close frequencies are played
beta particle—an electron or a positron
buoyant force—the upward force exerted by a fluid on an object that is wholly or partially submerged in that fluid
capacitor—a charge-storage device, often used in circuits
centrifugal force—a made-up force; when discussing circular motion, only talk about “centripetal” forces
centripetal force—the force keeping an object in uniform circular motion
coefficient of friction—the ratio of the friction force to the normal force. The coefficient of static friction is used when an object has no velocity relative to the surface it is in contact with; the coefficient of kinetic friction is used for a moving object
concave lens—a translucent object that makes the light rays passing through it diverge
conservative force—a force that acts on an object without causing the dissipation of that object’s energy in the form of heat
constructive interference—the overlap of two waves such that their peaks line up
convex lens—a translucent object that makes the light rays passing through it converge
critical angle—the angle past which rays cannot be transmitted from one material to another
current—the flow of positive charge in a circuit; the amount of charge passing a given point per unit time
cutoff frequency—the minimum frequency of light that, when absorbed, is capable of making an atom eject an electron
cycle—one repetition of periodic motion
daughter nucleus—the nucleus left over after an atom undergoes nuclear decay
de Broglie wavelength—the wavelength of a moving massive particle
density—the mass of an object divided by that object’s volume
destructive interference—the overlap of two waves so that the peaks of one wave line up with the troughs of the other
dipole—something, usually a set of charges, with two nonidentical ends
direction—the orientation of a vector
displacement—a vector quantity describing how far an object moved
Doppler effect—the apparent change in a wave’s frequency that you observe whenever the source of the wave is moving toward or away from you
elastic collision—a collision in which kinetic energy is conserved
electric field—a property of a region of space that affects charged objects in that particular region
electric flux—the amount of electric field that penetrates a certain area
electric potential—potential energy provided by an electric field per unit charge
electromagnetic induction—the production of a current by a changing magnetic field
electron—a subatomic particle that carries a negative charge
electron-volt—a unit of energy equal to the amount of energy needed to change the potential of an electron by one volt
energy—the ability to do work
entropy—a measure of disorder
equilibrium—when the net force and net torque on an object equal zero
equipotential lines—lines that illustrate every point at which a charged particle would experience a given potential
field—a property of a region of space that can affect objects found in that particular region
first law of thermodynamics—the change in the internal energy of a system equals the heat added to the system plus the work done on the system
flowing fluid—a fluid that’s moving
free-body diagram—a picture that represents one or more objects, along with the forces acting on those objects
frequency—the number of cycles per second of periodic motion; also, the number of wavelengths of a wave passing a certain point per second
friction—a force acting parallel to two surfaces in contact; if an object moves, the friction force always acts opposite the direction of motion
fulcrum—the point about which an object rotates
fundamental frequency—the frequency of the simplest standing wave
g—the acceleration due to gravity near the Earth’s surface, about 10 m/s2
gamma particle—a photon
gauge pressure—the pressure of a fluid at the bottom of a column due only to the fluid in the column
ground state energy—the lowest energy level of an atom
heat—a type of energy (related to molecular vibrations) that can be transferred from one object to another
heat engine—a system in which heat is added to a gas contained in a cylinder with a moveable piston; when the gas heats up, it expands, doing work by moving the piston up
impulse—the change in an object’s momentum
index of refraction—a number that describes by how much light slows down when it passes through a certain material
induced EMF—the potential difference created by a changing magnetic flux that causes a current to flow in a wire; EMF stands for “electro-motive force,” but the units of EMF are volts.
inductance—the property of an inductor that describes how good it is at resisting changes in current in a circuit
inductor—a coil in a circuit that makes use of induced EMF to resist changes in current in the circuit
inelastic collision—a collision in which kinetic energy is not conserved, as opposed to an elastic collision, in which the total kinetic energy of all objects is the same before and after the collision
inertia—the tendency for a massive object to resist a change in its velocity
internal energy—the sum of the kinetic energies of each molecule of a substance
ion—an electrically charged atom or molecule
ionization energy—the minimum amount of energy needed for an electron to escape an atom
isobaric process—a process during which the pressure of the system remains the same
isochoric process—a process during which the volume of the system remains the same
isotherm—a curve on a PV diagram for which the temperature is constant
isothermal process—a process during which the temperature of the system remains the same
isotope—an atom with the same atomic number as another atom but a different atomic mass
kinetic energy—energy of motion
Kirchoff’s laws—in a circuit, 1) at any junction, the current entering equals the current leaving; 2) the sum of the voltages around a closed loop is zero
Lenz’s law—the direction of the current induced by a changing magnetic flux creates a magnetic field that opposes the change in flux
longitudinal wave—when particles move parallel to the direction of a wave’s motion
magnetic field—a property of a region of space that causes magnets and moving charges to experience a force
magnetic flux—the amount of magnetic field that penetrates an area
magnitude—how much of a quantity is present; see “scalar” and “vector”
mass defect—the amount of mass that is destroyed and converted into kinetic energy in a nuclear decay process
mass number—the number of protons plus neutrons in an atom’s nucleus
mass spectrometer—a device used to determine the mass of a particle
moment of inertia—the rotational equivalent of mass
momentum—the amount of “oomph” an object has in a collision, equal to an object’s mass multiplied by that object’s velocity
net force—the vector sum of all the forces acting on an object
neutrino—A subatomic particle emitted during beta decay that affects only the kinetic energy of the products of the decay process
neutron—a subatomic particle found in an atom’s nucleus that has no electric charge
node—point on a standing wave where the medium through which the wave is propagating does not move
normal force—a force that acts perpendicular to the surface on which an object rests
nucleus—the small, dense core of an atom, made of protons and neutrons
oscillation—motion of an object that regularly repeats itself over the same path
parallel—the arrangement of elements in a circuit so that the charge that flows through one element does not flow through the others
Pascal’s principle—if a force is applied somewhere on a container holding a fluid, the pressure increases everywhere in the fluid, not just where the force is applied
peak—a high point on a wave
perfectly inelastic collision—a collision in which the colliding objects stick together after impact
period—the time it takes for an object to pass through one cycle of periodic motion; also, the time for a wave to propagate by a distance of one wavelength
photoelectric effect—energy in the form of light can cause an atom to eject one of its electrons, but only if the frequency of the light is above a certain value
photon—a particle of light; a photon has no mass
plane mirror—a flat, reflective surface
positron—like an electron, but with a positive charge
potential energy—energy of position
power—the amount of work done divided by the time it took to do that work; also, in a circuit, equal to the product of the current flowing through a resistor and the voltage drop across that resistor
pressure—the amount of force applied to a surface divided by the area of that surface
principal axis—the imaginary line running through the middle of a spherical mirror or a lens
principle of continuity—the volume flow rate is equal at all points within an isolated stream of fluid
proton—a subatomic particle found in an atom’s nucleus that carries a positive charge
PV diagram—a graph of a gas’s pressure versus its volume
real image—an image created by a mirror or a lens that is upside-down and can be projected onto a screen
refrigerator—like a heat engine, only work is done to remove heat
resistance—a property of a circuit that resists the flow of current
resistor—something put in a circuit to increase its resistance
restoring force—a force that restores an oscillating object to its equilibrium position
scalar—a quantity that has a magnitude but no direction
second law of thermodynamics—heat flows naturally from a hot object to a cold object but not from cold to hot; equivalently, the entropy of a system cannot decrease unless work is done on that system
series—the arrangement of elements in a circuit so that they are connected in a line, one after the other
specific gravity—the ratio of a substance’s density to the density of water
speed—the magnitude of an object’s velocity
spherical mirror—a curved, reflective surface
standing wave—a wave that, when observed, appears to have peaks and troughs that don’t move
static fluid—a fluid that isn’t flowing
temperature—a quantity related to the average kinetic energy per molecule of a substance
tension—a force applied by a rope or string
thermal expansion—enlargement of an object that is heated
time constant—a value related to how long it takes to charge or discharge a capacitor
torque—the application of a force at some distance from a fulcrum; if the net torque on an object isn’t zero, the object’s rotational velocity will change
total internal reflection—the reflection of light off a surface that occurs when the light cannot pass from a medium with a high index of refraction to one with a low index of refraction
transverse wave—occurs when the particles in a wave move perpendicular to the direction of the wave’s motion
trough—a low point on a wave
vector—a quantity that has both magnitude and direction
velocity—how fast an object’s displacement changes; equal to the derivative (slope) of an object’s position—time function
virtual image—an image created by a mirror or lens that is upright and cannot be projected onto a screen
volume flow rate—the volume of fluid flowing past a point per second
wave—a rhythmic up-and-down or side-to-side motion that moves through a material at constant speed
wavelength—a wave’s peak-to-peak or trough-to-trough distance
wave pulse—when a single peak travels through a medium
weight—the force due to gravity; equal to the mass of an object times g, the gravitational field
work—the product of the distance an object travels and the components of the force acting on that object directed parallel to the object’s direction of motion
work-energy theorem—the net work done on an object equals that object’s change in kinetic energy
work function—the minimum amount of energy needed for an electron to be ejected from the surface of a metal