AP Physics Vocabulary **NEW 2025**

average acceleration

change in velocity/change in time

acceleration due to gravity

the acceleration of an object in free fall that results from the influence of Earth's gravity (9.8 m/s^2 or 10 m/s^2)

acceleration-time graphs

graph showing change in acceleration over time

Action-Reaction Force pairs

forces equal in magnitude but opposite in direction

Air resistance

force that opposes the motion of objects that move through the air

Ampere

unit of electric current

Amplitude

the maximum displacement from equilibrium in a wave or oscilliation

angle

formed by two rays with the same endpoint

angle from the horizontal

angle between a line an horizontal axis

angular momentum

rotational momentum of a spinning or orbiting object

angular speed

rate of change of angular displacement

angular frequency

ω = 2πf, how fast something rotates in radians per second.

angular velocity

Rate of change of angular position, ω = Δθ/Δt.

apparent weight

normal force

applied force

a force which is applied to an object by a person or another object

atwood machine

a device that consists of two masses suspended over a pulley

angular acceleration

Rate of change of angular velocity, α = Δω/Δt.

angular displacement

change in angular position

angular distance

the total of all angular changes of a rotating body

average power

P=W/Δt work done over time interval

average velocity

displacement/time

balance point

the point of the bow where the weight is equally distributed.

best-fit line

the line that most closely approximates the data in a scatter plot

center of mass

the point in an object that moves as if all the object's mass were concentrated at that point

center of mass velocity

Velocity of the center of mass of a system of objects.

center of rotation

the fixed point in a rotation

centrifugal force

an apparent outward force in a rotating frame

centripetal acceleration

acceleration toward the center of a curved or circular path

centripetal force

A force that causes an object to move in a circle

CER format

A structure for writing a conclusion: Claim, Evidence, Reasoning

Change in Kinetic Energy

difference in an object kinetic energy ΔKE = ½ m (vf² - vi²)

change in momentum

Δp = mΔv, also known as impulse

circular motion

any motion in which an object is moving along a curved path

circular path

a path that follows a circular trajectory

closed system

a system where no mass or energy is exchanged witht he surroundings

coefficient of kinetic friction

A measure of the friction between two surfaces in motion

coefficient of static friction

the friction preventing an object from moving

collision

A situation in which two objects in close contact exchange energy and momentum

collision time

Duration of contact during a collision.

completely elastic collision

Type of collision in which both momentum and kinetic energy are conserved.

completely inelastic collision

a collision in which the colliding objects stick together after the collision and KE is lost

compression

A force that pushes on or squeezes a material.

conservation laws

laws sta

Conservation of Angular Momentum

Angular momentum remains constant in the absence of external torques.

Conservation of Energy

Energy cannot be created or destroyed, only transformed.

Conservation of Momentum

Momentum remains constant in an isolated system.

Conservative Forces

Forces where work done is independent of path (e.g., gravity).

Conservative Systems

Systems where total mechanical energy is conserved.

Constant Acceleration

Acceleration that does not change over time.

Constant Force

A force that remains unchanged.

Constant Speed

Motion at a steady speed.

Constant Velocity

Motion at a steady speed in a straight line.

Contact Forces

Forces that require physical contact (e.g., friction, tension).

Coordinate System

A reference framework for measuring motion.

Cosine

A trigonometric function used in physics calculations.

Cross-Sectional Area

The area of a slice through an object.

Data Tables

Tables used to organize scientific data.

Degrees

A unit of angular measurement.

Diagrams

Visual representations of concepts.

Digital Balance

An electronic device to measure mass.

Digital Caliper

A tool to measure small distances accurately.

Disk

A flat, circular object.

Direct Relationship

A relationship where one quantity increases with another.

Direction

The orientation of motion or force.

Displacement

The straight-line distance from an initial to a final position.

Distance

The total length traveled.

Distance above the Ground

Height measured from a reference point.

Dynamic Equilibrium

A state where an object moves at constant velocity.

Earth

The planet where we live, with g = 9.8 m/s².

Elastic Collisions

Collisions where kinetic energy is conserved.

Elastic Forces

Forces exerted by a stretched or compressed material.

Elastic Potential Energy

Energy stored in a stretched or compressed object, PE = ½ kx².

Energy

The capacity to do work.

Energy Transformations

The process of energy changing forms.

Equations

Mathematical relationships between variables.

Equilibrium

A state of balanced forces.

Equilibrium Point

The position where forces balance.

Equilibrium Position

The resting position in oscillations.

Exchange of Energy

Transfer of energy between objects or systems.

Exchange of Matter

Transfer of mass between systems.

Experimental Design

The setup of a scientific experiment.

Experimental Procedure

The steps in an experiment.

Experimental Uncertainty

The range of possible measurement error.

External Forces

Forces acting from outside a system.

F = mg

The equation for weight (force of gravity).

F = ma

Newton's Second Law of Motion.

Final Velocity

The velocity at the end of motion.

Force Net

The sum of all forces acting on an object.

Force

A push or pull acting on an object.

Force Constant

The stiffness of a spring, k.

Force Field

A region where a force acts on an object.

Force Interactions

How forces act between objects.

Force of Friction

The resistive force opposing motion.

Force of Gravity

The force pulling objects toward the Earth.

Force of Tension

The pulling force in a rope or string.

Free Response Questions (FRQ)

Open-ended physics questions requiring explanation.

Free-Body Diagram

A diagram showing forces acting on an object.

Freely Falling (Free-Fall)

Motion under only gravity's influence.

Frequency

Number of cycles per second, f = 1/T.

Frictionless

No resistance to motion.