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Scalar	A quantity with magnitude only		tp-ap-physics
Vector	A quantity with magnitude and direction		tp-ap-physics
Displacement	Change in position, a vector		tp-ap-physics
Velocity	Rate of change of position, with direction		tp-ap-physics
Acceleration	Rate of change of velocity		tp-ap-physics
Free fall	Motion under gravity alone; about 9.8 m/s^2 near Earth		tp-ap-physics
Projectile motion	Horizontal and vertical motions analyzed independently		tp-ap-physics
Newton's first law	An object keeps its motion unless a net force acts		tp-ap-physics
Newton's second law	Net force equals mass times acceleration		tp-ap-physics
Newton's third law	Forces come in equal and opposite pairs on different objects		tp-ap-physics
Inertia	Resistance to change in motion; related to mass		tp-ap-physics
Normal force	Contact force perpendicular to a surface		tp-ap-physics
Friction	Force opposing relative motion between surfaces		tp-ap-physics
Tension	Pulling force transmitted by a rope or string		tp-ap-physics
Weight	Gravitational force on an object, mg		tp-ap-physics
Free-body diagram	A sketch showing all forces on one object		tp-ap-physics
Centripetal acceleration	Acceleration toward the center of a circle, v^2/r		tp-ap-physics
Universal gravitation	F = Gm1m2/r^2		tp-ap-physics
Work	Force times displacement in the force direction		tp-ap-physics
Kinetic energy	Energy of motion, 1/2 mv^2		tp-ap-physics
Gravitational potential energy	Energy of position in a field, mgh near Earth		tp-ap-physics
Elastic potential energy	Energy stored in a spring, 1/2 kx^2		tp-ap-physics
Hooke's law	Spring force is proportional to stretch: F = -kx		tp-ap-physics
Work-energy theorem	Net work equals change in kinetic energy		tp-ap-physics
Conservation of energy	Total energy of an isolated system stays constant		tp-ap-physics
Power	Rate of doing work		tp-ap-physics
Momentum	Mass times velocity		tp-ap-physics
Impulse	Force times time; equals change in momentum		tp-ap-physics
Elastic collision	Kinetic energy is conserved		tp-ap-physics
Inelastic collision	Kinetic energy is not conserved		tp-ap-physics
Center of mass	The average position of an object's mass		tp-ap-physics
Torque	A force's turning effect, rF sin theta		tp-ap-physics
Rotational inertia	Resistance to change in rotation		tp-ap-physics
Angular momentum	Rotational inertia times angular velocity		tp-ap-physics
Equilibrium	Net force and net torque are zero		tp-ap-physics
Simple harmonic motion	Oscillation with restoring force proportional to displacement		tp-ap-physics
Period	Time for one cycle		tp-ap-physics
Frequency	Cycles per second, measured in hertz		tp-ap-physics
Amplitude	Maximum displacement from equilibrium		tp-ap-physics
Pendulum period	About 2 pi sqrt(L/g) for small swings		tp-ap-physics
Wavelength	Distance between matching points on a wave		tp-ap-physics
Wave speed	v = f times wavelength		tp-ap-physics
Transverse wave	Vibration perpendicular to travel direction		tp-ap-physics
Longitudinal wave	Vibration parallel to travel direction		tp-ap-physics
Superposition	Waves add together where they overlap		tp-ap-physics
Interference	Combining waves to reinforce or cancel		tp-ap-physics
Standing wave	A pattern with fixed nodes and antinodes		tp-ap-physics
Doppler effect	Change in observed frequency due to relative motion		tp-ap-physics
Diffraction	Spreading of waves around obstacles or through openings		tp-ap-physics
Refraction	Bending of waves when speed changes between media		tp-ap-physics
Snell's law	n1 sin theta1 = n2 sin theta2		tp-ap-physics
Total internal reflection	Light fully reflects at a boundary beyond the critical angle		tp-ap-physics
Converging lens	A lens that brings parallel rays together		tp-ap-physics
Electric charge	A property causing electric force; positive or negative		tp-ap-physics
Coulomb's law	Electric force between charges varies as q1q2/r^2		tp-ap-physics
Electric field	Force per unit charge		tp-ap-physics
Electric potential	Potential energy per unit charge, in volts		tp-ap-physics
Capacitor	A device that stores charge and energy in an electric field		tp-ap-physics
Current	Rate of flow of charge, in amperes		tp-ap-physics
Resistance	Opposition to current, in ohms		tp-ap-physics
Ohm's law	V = IR		tp-ap-physics
Electric power	P = IV		tp-ap-physics
Series circuit	Components in one path; same current		tp-ap-physics
Parallel circuit	Components on separate branches; same voltage		tp-ap-physics
Kirchhoff's junction rule	Current in equals current out at a junction		tp-ap-physics
Kirchhoff's loop rule	Voltage changes around a closed loop sum to zero		tp-ap-physics
Magnetic field	A region where moving charges or magnets feel force		tp-ap-physics
Magnetic force on a charge	F = qvB sin theta		tp-ap-physics
Faraday's law	A changing magnetic flux induces an emf		tp-ap-physics
Lenz's law	Induced current opposes the change that caused it		tp-ap-physics
Pressure	Force per unit area		tp-ap-physics
Density	Mass per unit volume		tp-ap-physics
Buoyant force	Upward force equal to the weight of displaced fluid		tp-ap-physics
Bernoulli's principle	Faster fluid flow goes with lower pressure		tp-ap-physics
Continuity equation	A1v1 = A2v2 for incompressible flow		tp-ap-physics
Temperature	A measure of average kinetic energy of particles		tp-ap-physics
Heat	Energy transferred due to temperature difference		tp-ap-physics
Zeroth law of thermodynamics	Systems in thermal equilibrium with a third are in equilibrium with each other		tp-ap-physics
First law of thermodynamics	Change in internal energy = heat added minus work done by the system		tp-ap-physics
Second law of thermodynamics	Entropy of an isolated system never decreases		tp-ap-physics
Heat engine	Converts heat into work		tp-ap-physics
Ideal gas law	PV = nRT		tp-ap-physics
Photoelectric effect	Light ejecting electrons from a metal, showing its particle nature		tp-ap-physics
Photon	A packet of light energy, E = hf		tp-ap-physics
Work function	Minimum energy to free an electron from a metal		tp-ap-physics
de Broglie wavelength	Wavelength of a particle: h/p		tp-ap-physics
Wave-particle duality	Matter and light show both wave and particle behavior		tp-ap-physics
Energy levels	Atoms have only certain allowed energies		tp-ap-physics
Emission spectrum	Light at specific wavelengths from excited atoms		tp-ap-physics
Mass-energy equivalence	E = mc^2		tp-ap-physics
Binding energy	Energy holding a nucleus together		tp-ap-physics
Half-life	Time for half of a radioactive sample to decay		tp-ap-physics
Fission	Splitting of a heavy nucleus		tp-ap-physics
Fusion	Joining of light nuclei		tp-ap-physics
Alpha decay	Emission of a helium nucleus		tp-ap-physics
Beta decay	A neutron becomes a proton, emitting an electron and antineutrino		tp-ap-physics