AP Physics

Physics

The study of matter, energy, and the interactions between them.

Kinematics

The study of motion without considering the forces that cause it.

Scientific Method

A systematic process for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge.

Displacement (Δx)

The change in position of an object, represented as a vector.

Velocity (v)

The rate of change of displacement, a vector quantity that includes both speed and direction.

Speed

A scalar quantity representing how fast an object is moving, regardless of direction.

Acceleration (a)

The rate of change of velocity, can be positive (increasing velocity) or negative (decelerating).

Position vs. Time Graph

Graphical representation of an object's position over time, where the slope indicates velocity.

Velocity vs. Time Graph

Graphical representation of an object's velocity over time, where the area under the curve indicates displacement.

Newton's First Law of Motion

An object at rest will stay at rest, and an object in motion will stay in motion unless acted upon by an unbalanced force.

Newton's Second Law of Motion

The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

Net Force (F_net)

The vector sum of all forces acting on an object.

Inertia

The property of an object that resists changes to its state of motion.

Free-Body Diagram

A visual representation showing all the forces acting on an object.

Gravitational Force (Weight)

The force due to gravity acting on an object, calculated as F_g = m * g.

Normal Force (F_N)

The force exerted by a surface perpendicular to an object resting on it.

Frictional Force

A force that opposes the relative motion of two surfaces in contact.

Tension Force

The force transmitted through a rope, string, or cable when it is pulled tight.

Action and Reaction Forces

Forces that are equal in magnitude and opposite in direction, acting on two different objects.

Projectile Motion

A form of two-dimensional motion involving an object moving under the influence of gravity.

Scalar vs. Vector

Scalars have only magnitude, while vectors have both magnitude and direction.

Average Velocity Equation

Average velocity is calculated as displacement divided by time: v_avg = Δx/Δt.

Average Acceleration Equation

Average acceleration is calculated as the change in velocity divided by the time interval: a_avg = Δv/Δt.

Equations of Motion

Equations that relate displacement, velocity, acceleration, and time for an object under constant acceleration.

Uniform Motion

Motion at a constant speed in a straight line.

Acceleration due to Gravity (g)

The acceleration of an object due to Earth's gravity, approximately -9.8 m/s².

Range (for projectile motion)

The horizontal distance traveled by a projectile before it hits the ground.

Component Method (of vectors)

A technique to break vectors into their horizontal and vertical components using trigonometry.

Magnitude of a Vector

The length or size of a vector, calculated using the Pythagorean theorem for its components.

Directional Angle of a Vector

The angle that a vector makes with a reference direction, calculated using trigonometric functions.

Constant Velocity

When an object moves at a steady speed in a straight line.

Constant Acceleration

When the acceleration of an object remains unchanged over time.

Equations of Motion for Constant Acceleration

Formulas that describe how an object's displacement, velocity, and acceleration are related under constant acceleration.

Kinematic Equations

Mathematical equations that relate displacement, time, initial velocity, final velocity, and acceleration.

Newton's Law of Universal Gravitation

The force of gravity between two objects is proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

Friction Coefficient (μ)

A measure of the frictional force between two surfaces in contact, determining how much force is needed to slide one surface over the other.

Work Done by a Force (W)

The energy transferred by a force acting through a distance: W = F * d * cos(θ), where θ is the angle between force and displacement.

Power (P)

The rate at which work is done or energy is transferred, calculated as P = W/t.

Energy

The capacity to do work.

Kinetic Energy (KE)

The energy an object possesses due to its motion, calculated as KE = ½ mv^2.

Potential Energy (PE)

The energy stored in an object due to its position or configuration, often due to gravity: PE = mgh.

Momentum (p)

The product of an object's mass and its velocity: p = mv.

Conservation of Momentum

In a closed system, the total momentum before an event is equal to the total momentum after the event.

Collision

An event where two or more bodies exert forces on each other for a relatively short time.

Elastic Collision

A collision in which both momentum and kinetic energy are conserved.

Inelastic Collision

A collision in which momentum is conserved but kinetic energy is not.

Impulse (J)

The change in momentum of an object when a force is applied over a period of time, calculated as J = F * t.

Rotational Motion

Motion about an axis, characterized by angular displacement, velocity, and acceleration.

Torque (τ)

The rotational equivalent of linear force, calculated as τ = r * F, where r is the distance from the pivot.

Center of Mass

The point at which an object's mass is evenly distributed in all directions.

Equilibrium

A state in which opposing forces or influences are balanced.

Newton's Laws of Motion

Three laws formulated by Newton that describe the relationship between an object's motion and the forces acting on it.

Thermal Energy

The total kinetic energy of particles in a substance, which contributes to its temperature.

Heat Transfer

The movement of thermal energy from one object to another, occurring via conduction, convection, or radiation.

Conduction

The transfer of heat through direct contact between materials.

Convection

The transfer of heat through fluid (liquid or gas) due to the movement of the fluid itself.

Radiation

The transfer of energy through electromagnetic waves, allowing heat to pass through a vacuum.

Specific Heat Capacity

The amount of heat required to change the temperature of a unit mass of a substance by one degree Celsius.

Phase Changes

Transitions between solid, liquid, and gas states due to changes in temperature or pressure.

Ideal Gas Law

A relationship between pressure, volume, temperature, and the number of moles of a gas, represented as PV = nRT.

Pressure (P)

The force exerted per unit area, calculated as P = F/A.

Temperature (T)

A measure of the average kinetic energy of the particles in a substance.

Thermodynamics

The study of heat, energy, and the relationships between them.

First Law of Thermodynamics

Energy cannot be created or destroyed; it can only be transferred or transformed.

Second Law of Thermodynamics

The total entropy of an isolated system always increases over time.

Entropy (S)

A measure of randomness or disorder in a system.

Mechanical Energy (E_mech)

The sum of kinetic and potential energy in a system.

Energy Conservation

The principle stating that energy cannot be created or destroyed, only transformed from one form to another.

Hooke's Law

The force exerted by a spring is directly proportional to the displacement from its equilibrium position: F = -kx.

Simple Harmonic Motion (SHM)

Periodic motion in which the restoring force is directly proportional to the displacement.

Wave

A disturbance that transfers energy through a medium or space.

Frequency (f)

The number of complete cycles of a periodic wave that occur in a given time interval.

Wavelength (λ)

The distance between successive crests or troughs of a wave.

Amplitude (A)

The maximum displacement of a wave from its equilibrium position.

Sound Waves

Longitudinal waves that transmit sound through a medium.

Electromagnetic Waves

Transverse waves that do not require a medium and can travel through a vacuum.

Reflection

The bouncing back of a wave when it hits a barrier.

Refraction

The bending of a wave as it passes from one medium to another due to a change in speed.

Interference

The process in which two or more waves overlap and combine to form a new wave pattern.

Doppler Effect

The change in frequency or wavelength of a wave in relation to an observer moving relative to the wave source.

Quantum Mechanics

The branch of physics that deals with the behavior of particles at very small scales.

Relativity

The theory developed by Einstein that describes the laws of physics in different frames of reference, especially at high speeds.

Standard Model of Particle Physics

The theory describing the fundamental particles and forces of the universe.

Photon

A particle representing a quantum of light or other electromagnetic radiation.

Neutrino

An electrically neutral particle with a very small mass, produced in nuclear reactions.

Higgs Boson

A particle associated with the Higgs field, which gives mass to other particles.

String Theory

A theoretical framework in which point-like particles are replaced by one-dimensional strings.

Astrophysics

The branch of astronomy that deals with the physical properties and behavior of celestial bodies and the universe.

Dark Matter

A form of matter that does not emit light or energy, making it undetectable by conventional methods.

Dark Energy

A mysterious form of energy that makes up a large part of the universe and is thought to be responsible for its accelerated expansion.

Big Bang Theory

The prevailing cosmological model describing the origin and evolution of the universe.

Redshift

The phenomenon where light from an object is shifted to longer wavelengths, indicating that the object is moving away from the observer.

Cosmic Microwave Background Radiation

The thermal radiation filling the universe, a remnant from the Big Bang.