AP Physics 1 vocab: 80+ physics terms by unit

AP Physics 1 is a rigorous introduction to complex terms, concepts, and problem-solving approaches in the physical sciences. While many students begin AP Physics 1 with a basic foundation from previous science classes, the range of topics extends well beyond that, focusing on technical vocabulary and algebra-based analysis. Throughout this course, you’ll deepen your understanding not just of fundamental principles, such as why objects move, spin, or float the way they do, but also of how to quantitatively determine the elements of forces and motion.

Understanding physics can be particularly challenging because many physics-specific terms have precise meanings. Often, the exact scientific definition of a term, such as “work,” “energy,” or “force,” differs from how it is used in everyday language. Recognizing these differences and mastering accurate physics vocabulary are absolute necessities for both grasping the main topics and performing well on the AP Physics 1 exam. To support your progress, we’ve created a detailed, physics vocab study guide organized unit by unit to reinforce major AP Physics 1 topics, all designed to enhance your preparation for your course assessments and final exam.

80+ vocab words for AP Physics 1

Below are the key terms to know, broken up by the major units taught in AP Physics 1. Included are also brief introductions to each unit, as well as relevant equations and examples.

Unit 1: Kinematics

At a high level, kinematics is the study of motion, including displacement, velocity, and acceleration. This foundational unit in AP Physics 1 explores how objects move (why they move is the subject of Unit 2), and how to predict or control their movement over specific distances and speeds using core formulas and equations.

Key vocabulary terms:

1. Motion: Motion describes the change in position of an object over time and how objects travel through space.
2. Scalars vs. vectors: Scalars refer to quantities that have only magnitude (size), such as distance or speed, without any direction. Vectors are quantities with both magnitude and direction, such as displacement or velocity.
3. Displacement vs. distance: Displacement indicates a straight-line change from an object’s initial to final position, while distance is a scalar quantity representing the total path length traveled, regardless of direction.
4. Average velocity vs. instantaneous velocity: Average velocity is calculated as total displacement divided by the time interval. Instantaneous velocity is the velocity of an object at a specific moment, a distinction important in physics for interpreting motion graphs and real-time movement.
5. Average acceleration vs. instantaneous acceleration: In physics terms, average acceleration is the overall rate of change in velocity during a time period, while instantaneous acceleration refers to the acceleration at a particular instant, represented graphically by the slope of a tangent line.
   Remember: In physics, acceleration doesn’t just refer to speeding up, like how we would say a car accelerates. It more precisely describes a change in velocity, which may indicate that an object is speeding up, slowing down, or changing direction.
6. Motion maps and dot diagrams: These useful plots visualize an object’s movement as a series of dots spaced at equal time intervals; the spacing between dots indicates speed, while arrows show velocity and acceleration, aiding in visualizing motion concepts.
7. Position-time graphs (slope meaning): A position-time graph is a fundamental physics term where an object’s position (y-axis) is plotted against time (x-axis). The slope of this graph represents the object’s velocity: a line connecting two points gives the average velocity, and a line tangent to one point gives the instantaneous velocity.
8. Velocity-time graphs (slope and area meaning): In these visual representations, an object’s velocity (y-axis) is plotted against time (x-axis). The slope reveals acceleration (straight lines mean constant acceleration; curves indicate changing acceleration). Calculating the area under the curve provides displacement.
9. Constant-acceleration motion relationships: Situations in which an object’s acceleration remains constant over the time interval studied, allowing for predictable motion equations.
10. Free fall acceleration: In physics, free fall acceleration refers to the constant rate at which objects accelerate toward Earth when dropped near its surface (about 9.8 m/s², directed downward).
11. Projectile motion (independent horizontal/vertical motion): Projectile motion is a classic physics term describing how objects launched into the air move with independent x- (horizontal) and y- (vertical) components, influenced by initial velocity and gravity.
12. Relative velocity and reference frames: These terms describe how an object’s motion is measured from different perspectives or moving reference frames (like observing a passing car from your own moving vehicle), which is crucial for understanding relative movement.

Unit 2: Force and Translational Dynamics

Dynamics is the study of forces, including gravity, friction, and tension, and their effects on motion. You’ll revisit the concepts from Unit 1 to explore force, which describes the interaction between objects and how these interactions cause changes in motion.

Key vocabulary terms:

1. Force: A push or pull that may cause an object to accelerate. Forces can include contact forces, such as tension and friction, as well as non-contact forces, such as gravity.
2. Newton’s first law (inertia): Inertia refers to an object’s resistance to changes in its state of motion. According to Newton’s first law, an object at rest remains at rest, and an object in motion continues with constant velocity unless acted upon by a net external force.
3. Newton’s second law (net force causes acceleration): The acceleration of an object depends on the net force acting on it and its mass. Greater net force produces greater acceleration, while higher mass results in less acceleration:
   ΣF = ma (more net force leads to more acceleration; more mass leads to less acceleration)
4. Newton’s third law (interaction pairs): For every action force, there is an equal and opposite reaction force. These interaction pairs include forces such as a rope pulling on a box while the box pulls back on the rope, always acting on different objects.
5. Free-body diagrams: A simplified drawing representing all forces acting on an object using labeled arrows (force vectors). For example, a person walking experiences gravity (downward), normal force (upward), and friction (forward).
6. Normal force and contact forces: The normal force is the perpendicular support force exerted by a surface on an object. Contact forces also include friction, tension in ropes or cables, spring forces, and applied forces.
7. Static friction vs. kinetic friction: Friction opposes the sliding (or attempted sliding) of two surfaces against each other. Static friction resists initial movement, while kinetic friction acts during motion.
8. Tension forces in ropes/cables: Tension is the pulling force transmitted through a rope, string, or cable when stretched tight. Tension acts along the length of the rope, pulling on whatever the rope is attached to. On a pulley that has mass, the rope’s tension also exerts a torque that turns the pulley (Unit 5).
9. Inclined plane force components: For an object on a slope (angled surface), gravity splits into two components, one parallel to the incline (causing sliding) and one perpendicular (balanced by the normal force).
10. Uniform circular motion (centripetal acceleration): Motion along a circular path at constant speed requires a net inward force. This centripetal force can come from tension in a string or cable, gravity, friction, the normal force, or a combination of forces.
11. Centripetal force: The net inward force on an object moving in a circle, keeping it on its circular path by providing the necessary acceleration toward the center of the circle.
12. Weight vs. mass (gravity near Earth): Weight is the gravitational force acting on an object (equal to mass times gravitational acceleration), while mass is the amount of matter present. Mass remains constant, but weight changes with the strength of the gravitational field.
13. Newton’s law of universal gravitation: Every object in the universe attracts every other object with a force proportional to the product of their masses and inversely proportional to the square of the distance between their centers of mass. Gravitational forces can create both linear motion and rotational effects.

Unit 3: Work, Energy, and Power

You’ll explore the definitions and interconnections between work, energy, power, and the conservation of energy.

Key vocabulary terms:

1. Work as energy transfer: Work involves the transfer of energy through the application of force over a distance.
2. Kinetic energy (energy of motion): The energy an object possesses due to its motion. Changes in kinetic energy, governed by the work-energy theorem, are central to understanding how energy is conserved between transfers and movements.
3. Potential energy: Energy stored in a system because of the positions of its objects or its shape. Potential energy is an integral part of the total mechanical energy and the principle of conservation of energy.
4. Gravitational potential energy (energy from height): The potential energy an object has due to its height in a gravitational field. This form of stored energy transforms as objects move.
5. Elastic potential energy (energy stored in springs): Potential energy stored in stretched or compressed elastic materials, such as springs. This type of energy demonstrates how mechanical systems obey the conservation of energy.
6. Work-energy theorem concept: The net work done on an object (the total work done by all the forces on it) equals the change in its kinetic energy. Recall that the delta symbol Δ denotes change:
   ΣW = ΔKE (positive net work increases speed, negative net work decreases speed)
7. Conservative vs. nonconservative forces: Conservative forces (like gravity and spring force) do work that depends only on an object’s initial and final positions and do not decrease total mechanical energy, thus upholding the conservation of energy. Nonconservative forces (such as friction and air resistance) do work that depends on the path taken and convert mechanical energy into other forms, such as thermal energy or sound, rather than causing a loss of total energy.
8. Mechanical energy (total of motion + stored energy): The sum of kinetic and potential energies in a system:
   ME = KE + PE (remains constant if only conservative forces act)
9. Power (rate of energy transfer): Power measures how quickly work is done or how fast energy is transferred.
10. Energy bar charts/LOL diagrams: Visual tools that represent how different forms of energy, such as kinetic, gravitational potential, elastic potential, and thermal, are stored, transferred, and transformed within a system. The name “LOL” comes from the diagram’s shape: an L-shaped bar chart for the initial energy, an O (circle) showing what is in the system, and an L-shaped bar chart for the final energy. Energy that enters or leaves the system, such as work done by an outside force, is shown separately.
11. Hooke’s law concept (spring restoring force, from Unit 2): The force exerted by a spring is proportional to its displacement:
    F = −kx (the negative sign indicates the spring force acts in the opposite direction to stretch or compression)

Unit 4: Linear Momentum

This unit explores the relationships among force, time, momentum, and the conservation of energy, as well as how to apply the law of conservation of momentum and the concept of center of mass to analyze physical systems. Angular momentum, the rotational version of momentum, comes later, in Unit 6.

Key vocabulary terms:

1. Momentum as “mass in motion”: Momentum represents the quantity of motion an object possesses and is calculated as mass multiplied by velocity:
   p = mv (momentum is a vector, indicating it has both magnitude and direction). Its rotational analog, angular momentum, comes up in Unit 6.
2. Impulse as “force applied over time”: Impulse measures the effect of a force acting on an object during a specific time interval:
   J = FΔt, where F is the average force (impulse changes an object’s momentum).
3. Impulse-momentum connection: Impulse directly equals the change in momentum for a system:
   J = Δp (larger forces or longer durations produce greater changes in momentum).
4. Conservation of energy: The foundational principle that energy in a system cannot be created or destroyed but only transferred or transformed. The law of conservation of energy interplays with the conservation of momentum during collisions and other interactions.
5. Conservation of momentum in closed systems: In any closed system with no net external force, the total momentum remains constant throughout an interaction.
6. Elastic vs. inelastic collisions: In elastic collisions, both momentum and kinetic energy are conserved, following the laws of conservation of energy and conservation of momentum. In inelastic collisions, momentum is conserved, but kinetic energy is not: some of it transforms into thermal energy, sound, or deformation.
   For example, two ice cubes gliding into each other on a frictionless surface experience a nearly elastic collision, while two cars that crumple in a crash experience an inelastic collision.
7. Perfectly inelastic collisions (objects stick together): A perfectly inelastic collision occurs when colliding objects stick together after impact and move as a single mass. Here, total momentum is conserved, but the greatest possible amount of kinetic energy is lost (all of it only if the combined object ends up at rest).
   Picture two lumps of dough colliding and sticking together as one lump.
8. Explosions/recoil and separation from rest: When objects at rest push apart, such as skaters pushing off from one another, the system’s total momentum remains zero before and after, demonstrating conservation of momentum. Kinetic energy isn’t conserved: it increases, because stored energy (here, from the skaters’ muscles) is converted into kinetic energy.
9. Center of mass motion idea: The center of mass defines the average position of all mass within a system. The system’s translational motion can be analyzed as if all its mass were located at this point. The center of mass moves at a constant velocity unless a net external force acts on the system.
10. Force-time graphs (area meaning impulse): On a force versus time graph, the area under the curve represents impulse:
    Impulse = area = Δp (this visual approach helps you see how forces change an object’s momentum)
11. Momentum vs. kinetic energy in collisions: In collisions within closed systems, momentum is always conserved (as stated in the law of conservation of momentum). Kinetic energy is conserved only in elastic collisions (depending on the square of speed), making it more easily changed than momentum. These ideas are paralleled in rotational scenarios involving angular momentum and rotational kinetic energy.

Unit 5: Torque and Rotational Dynamics

In this unit, you’ll apply the tools, techniques, and mathematical models learned in previous units to analyze the dynamics of rotating bodies. This unit includes a special focus on torque, rotational inertia, and what causes objects to rotate.

Before diving deeper into rotational concepts and vocabulary, let’s define some critical variables:

θ (theta symbol) = commonly represents angles in rotational motion

ω = denotes angular velocity

α = symbolizes angular acceleration

In rotational motion, movements are best analyzed in terms of angles, such as rotational displacement, angular velocity, and angular acceleration, because every point on a rotating rigid object turns through the same angle, even though points farther from the axis travel farther. This requires calculations based on circular or rotational paths to determine quantities such as angular displacement, distance traveled, and rotational velocity. Torque and angular momentum play crucial roles in understanding how and why objects spin or remain at rest.

Key vocabulary terms:

1. Angular displacement: The change in an object’s rotational position, represented as the angle (in radians) between its initial and final orientations.
   Δθ = θf − θi
2. Angular velocity: The rate at which angular displacement changes, providing a measure of how quickly an object rotates around an axis.
   ω = Δθ/Δt
3. Angular acceleration: The rate at which angular velocity changes over time, directly related to net torque acting on the object.
   α = Δω/Δt
4. Torque: The “twisting effect” of a force applied to an object, which causes angular acceleration. Torque is fundamental for changing angular momentum.
   τ = rFsinθ
5. Lever arm/moment arm: The perpendicular distance from the axis of rotation to the line where force is applied; a longer lever arm increases the magnitude of torque.
6. Rotational equilibrium (balanced torques): A condition in which the net torque on an object is zero, meaning there is no change in its rotation (angular velocity stays constant).
   Στ = 0
7. Static equilibrium (balanced forces AND torques): Occurs when an object experiences zero net force and zero net torque, resulting in no linear or rotational acceleration.
   ΣF = 0 and Στ = 0
8. Rotational kinematics concepts: Describes rotational motion by using angular equivalents of position, velocity, and acceleration (represented by θ, ω, α) and includes constant angular acceleration equations that mirror those in linear kinematics.
9. Tangential vs. centripetal acceleration in rotational dynamics: Tangential acceleration changes the speed of a point moving along the circular path and acts along the tangent to the circular path (aₜ = rα). Centripetal acceleration changes only the direction and always points toward the center of the circle (a𝑐 = v²/r = rω²).
10. Newton’s second law for rotation: Connects net torque to angular acceleration (Στ = Iα), where I is the rotational inertia. A net torque produces a change in angular momentum over time.

Unit 6: Energy and Momentum of Rotating Systems

You’ll explore how torque, angular momentum, and the center of mass shape the behavior of objects rotating around an axis, linking these key rotational dynamics concepts to their linear counterparts, such as momentum and energy.

Key vocabulary terms:

1. Rotational motion: The movement of an object as it spins around an axis, such as the rotation of a planet or a wheel, influenced by forces and the distribution of mass relative to the axis of rotation.
2. Moment of inertia, or rotational inertia (depends on mass distribution): The measure of an object’s resistance to changes in its rotational motion, determined by its mass and how that mass is distributed relative to the axis of rotation.
3. Rotational kinetic energy (energy of spinning): The kinetic energy associated with an object’s rotation, calculated by:
   KEᵣₒₜ = ½Iω²
   This form of energy works in concert with translational kinetic energy in systems that both spin and move linearly, thereby preserving energy conservation.
4. Angular momentum concept: The rotational analog of linear momentum, defined by the product of an object’s moment of inertia and its angular velocity:
   L = Iω
5. Conservation of angular momentum: A fundamental principle stating that if no net external torque acts on a system, its total angular momentum remains constant over time, regardless of changes in configuration or speed.
6. Angular impulse concept: Angular impulse is produced by applying torque over a period of time, causing a change in angular momentum:
   τΔt = ΔL
7. Rolling without slipping condition (linking rolling and spinning): When an object rolls smoothly without sliding, its linear speed and angular speed are related by v = rω. This relationship connects rotational variables with translational motion and links back to both torque and center of mass.
8. Total kinetic energy in rolling objects (translation + rotation): For rolling objects, total kinetic energy combines translation and rotation:
   KEₜₒₜ = ½mv² + ½Iω²
9. Rotational work concept: Work done by a torque during rotation is the product of torque and angular displacement:
   W = τΔθ
10. Rotational power concept (an extension beyond the AP Physics 1 course framework): Rotational power measures how quickly rotational work is performed and is given by the product of torque and angular velocity:
    P = τω
11. Parallel axis theorem concept (from Unit 5): For an axis that is parallel to an axis through the center of mass, at a distance d from it, an object’s rotational inertia is given by:
    I = Icm + Md²

Unit 7: Oscillations

All the tools, techniques, and models you’ve learned in previous units are combined to analyze a new kind of motion: simple harmonic motion, or SHM.

Key vocabulary terms:

1. Simple harmonic motion (SHM): A type of periodic motion where the restoring force is proportional to displacement and always points toward equilibrium (motion repeats in a regular cycle).
2. Restoring force idea (pulls back toward equilibrium): A force that always acts to return an object to its equilibrium position (opposite the direction of displacement).
3. Mass-spring oscillation behavior: A mass on a spring moves back and forth around equilibrium with a restoring force given by F = −kx, producing SHM if friction is small.
4. Pendulum oscillation behavior (small-angle approximation): A pendulum swings back and forth, and for small angles, its motion is approximately SHM (gravity provides the restoring force).
5. Amplitude: The maximum displacement from equilibrium (the “largest distance” the object moves from the center).
6. Period: The time it takes to complete one full cycle of motion (T).
7. Frequency: The number of cycles per second (f = 1/T), measured in hertz (Hz). For example, a pendulum that completes two full swings every second has a frequency of 2 Hz.
8. Angular frequency concept: How fast the object moves through cycles in radians per second:
   ω = 2πf
9. Phase (position in the cycle): A measure of where an object is in its oscillation cycle at a given time (shows how far through the pattern it is).
10. Damping and resonance (beyond the AP Physics 1 course framework, but useful context): Damping is the gradual loss of amplitude due to energy dissipation (e.g., friction or air resistance). Resonance occurs when a system is driven at its natural frequency, leading to a large increase in amplitude.

Unit 8: Fluids

In the final unit of the course, you’ll investigate the behavior and motion of materials that can change shape, and analyze how these properties interact with other objects in various physical systems.

Key vocabulary terms:

1. Density: A foundational physics term, density describes the amount of mass contained within a given volume of a substance:
   ρ = m/V
2. Pressure: In physics, pressure refers to the perpendicular force exerted per unit area on a surface:
   P = F/A
3. Hydrostatic pressure (variation with depth): This physics concept explains how the pressure in a stationary fluid increases as depth increases:
   P = P₀ + ρgh
4. Pascal’s principle: Pascal’s principle states that any change in pressure applied to an enclosed fluid is transmitted equally throughout the entire fluid. This principle is fundamental to hydraulic lift systems.
5. Buoyant force: In fluid physics, buoyant force is the upward force a fluid exerts on an object submerged in it, caused by differences in pressure at varying depths. This effect enables large objects, like boats, and tiny items, like rubber ducks, to float.
6. Archimedes’ principle: This classic physics principle states that the buoyant force acting on an object equals the weight of the fluid displaced by the object. Hydrostatic weighing, which estimates a person’s body fat percentage by weighing them underwater to find their body density, relies on Archimedes’ principle.
7. Flow rate: Flow rate is a key physics concept describing how much fluid passes a specific point per unit time, typically measured as volume per time:
   Q = A v
8. Continuity equation (relation between flow speed and area): According to this physics law for incompressible fluids, the flow rate remains constant; thus, if the cross-sectional area decreases, the speed of flow increases:
   A₁v₁ = A₂v₂
9. Bernoulli’s principle: This important physics term explains that in a moving fluid at a constant height, increased speed results in decreased pressure, as energy is distributed among pressure, kinetic energy (speed), and gravitational potential energy (height):
   P₁ + ρgy₁ + ½ρv₁² = P₂ + ρgy₂ + ½ρv₂²

The core physics terms listed above hold the key to understanding the laws that govern movement, rotation, and how materials behave under different forces and conditions. Use these terms as a helpful review after each unit, and feel free to add more as you continue your studies.

How to study science vocab

When preparing for the AP Physics 1 exam or any other science assessment that uses specialized terminology, a list of vocabulary words and definitions is a good place to start. However, simply reading a study guide or relying on last-minute memorization typically results in short-term retention rather than a deep, long-term understanding of the concepts.

To truly master AP Physics 1 exam vocabulary, you should try to engage with key terms in context. Because much of the terminology in physics can be niche and esoteric, recognizing and using these words in everyday contexts effectively can require extra effort. Consider these strategies to reinforce your knowledge of physics vocabulary beyond the classroom:

• Explore academic papers that utilize AP Physics 1 exam concepts to solve practical research problems, especially those that use algebraic methods as opposed to advanced calculus
• Read popular science magazines such as Scientific American to see real-world applications of physics principles
• Watch documentary series like “NOVA” or “Cosmos: A Spacetime Odyssey” that break down challenging topics like astrophysics into accessible language
• Find YouTube channels by science educators who demonstrate experiments and explain the underlying theories

Along with increasing your exposure to real scientific applications, utilize these proven techniques to master vocabulary:

• Practice active recall: Create digital or handwritten flashcards including definitions, formulas, and sample problems, and monitor which terms you find most challenging.
• Construct word maps: Link related concepts and topics to visualize their connections.
• Work through a variety of practice questions: Familiarize yourself with the ways AP Physics 1 exam vocabulary appears in both multiple-choice and free-response sections. Keep the official AP Physics 1 equation sheet beside you as you practice, since College Board provides it, along with a calculator, on exam day.

By combining long-term comprehension strategies with efficient memorization, learning the extensive vocabulary required for Physics 1 becomes far more manageable, turning what first seems like an unclimbable mountain of terms into a set of achievable, familiar concepts.

Final thoughts

While many students may think of studying vocabulary as something limited to humanities or social studies, mastering key terms is equally important in AP Physics 1. Each topic, such as motion, fluid principles, and oscillations, requires students to understand, memorize, and actively apply a broad array of physics vocabulary. Preparing for the exam means going beyond passive memorization; real success comes from recognizing important terms not just in isolation, but also within the context of complex exam questions to ensure full comprehension.

As you study for your exam, focus on building strong connections across different units and identifying parallels between concepts, such as analogies between rotational and linear motion. This integrated strategy will help you tackle each subtopic and develop a deeper conceptual understanding. With consistent and dedicated practice over several weeks, your understanding of AP Physics 1 will strengthen, and the connections between the different pieces of content will start to come together, making the path toward a high score much smoother. May the force be with you!