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🎡AP Physics 1
Key Terms

568 essential vocabulary terms and definitions to know for your AP Physics 1 exam

Study AP Physics 1
Practice Vocabulary
🎡AP Physics 1
Key Terms by Unit

📚Unit 1 – Kinematics

1.1 Scalars and Vectors in One Dimension

TermDefinition
accelerationThe rate of change of velocity with respect to time.
directionThe orientation or path along which a quantity is measured, which depends on the choice of reference frame.
displacementA vector quantity representing the change in position of an object from its initial to final location.
distanceA scalar quantity representing the total length of the path traveled by an object.
magnitudeThe size or amount of a measured quantity, which can vary depending on the observer's reference frame.
one-dimensional coordinate systemA reference system used to describe positions and directions along a single axis, typically represented as a number line.
opposite directionsDirections that are 180 degrees apart on a coordinate system, represented by opposite signs in one-dimensional calculations.
positionA vector quantity describing the location of an object relative to a reference point.
scalarA physical quantity that has magnitude only, without direction.
speedA scalar quantity representing the rate at which an object covers distance.
vectorA quantity that has both magnitude and direction, which can be represented as the sum of perpendicular components.
vector componentThe projection of a vector along a specific axis or direction, which in one dimension is indicated by the sign of the value.
vector sumThe result of adding two or more vectors together, taking into account both magnitude and direction.
velocityA vector quantity that describes both the speed and direction of an object's motion.

1.2 Displacement, Velocity, and Acceleration

TermDefinition
accelerationThe rate of change of velocity with respect to time.
average accelerationThe change in velocity of an object divided by the time interval over which that change occurs.
average velocityThe displacement of an object divided by the time interval over which that displacement occurs.
displacementA vector quantity representing the change in position of an object from its initial to final location.
instantaneous accelerationThe acceleration of an object at a specific instant in time, equal to the slope of the tangent line to a velocity-time graph.
instantaneous velocityThe velocity of an object at a specific instant in time, equal to the slope of the tangent line to a position-time graph.
object modelA simplification in physics where an object is treated as a single point with properties like mass and charge, ignoring size, shape, and internal structure.
positionA vector quantity describing the location of an object relative to a reference point.
time intervalThe duration of time over which a change in an object's motion is measured.
velocityA vector quantity that describes both the speed and direction of an object's motion.

1.3 Representing Motion

TermDefinition
accelerationThe rate of change of velocity with respect to time.
constant accelerationMotion in which an object's acceleration remains the same throughout the time interval being analyzed.
displacementA vector quantity representing the change in position of an object from its initial to final location.
gravitational accelerationThe constant downward acceleration of objects near Earth's surface due to gravity, approximately 10 m/s².
instantaneous accelerationThe acceleration of an object at a specific instant in time, equal to the slope of the tangent line to a velocity-time graph.
instantaneous velocityThe velocity of an object at a specific instant in time, equal to the slope of the tangent line to a position-time graph.
kinematic equationsMathematical equations used to describe the motion of an object under constant acceleration in one dimension.
motion diagramsVisual representations of an object's motion showing its position at successive time intervals.
positionA vector quantity describing the location of an object relative to a reference point.
velocityA vector quantity that describes both the speed and direction of an object's motion.

1.4 Reference Frames and Relative Motion

TermDefinition
accelerationThe rate of change of velocity with respect to time.
coordinate systemA reference framework used to resolve vectors into their perpendicular components, typically using horizontal and vertical axes.
directionThe orientation or path along which a quantity is measured, which depends on the choice of reference frame.
inertial reference frameA reference frame in which Newton's laws of motion apply; a frame that is either at rest or moving at constant velocity.
magnitudeThe size or amount of a measured quantity, which can vary depending on the observer's reference frame.
observed velocityThe velocity of an object as measured by an observer in a particular reference frame, determined by combining the object's velocity with the observer's frame velocity.
observerA person or point of view from which physical phenomena are measured and described.
vector additionThe mathematical process of combining two or more vectors to find a resultant vector, used when combining velocities from different reference frames.

1.5 Vectors and Motion in Two Dimensions

TermDefinition
accelerationThe rate of change of velocity with respect to time.
coordinate systemA reference framework used to resolve vectors into their perpendicular components, typically using horizontal and vertical axes.
kinematic relationshipsMathematical equations that describe the motion of objects in terms of displacement, velocity, acceleration, and time.
motion componentsThe separation of two-dimensional motion into independent one-dimensional motions along perpendicular axes.
perpendicular componentsThe parts of a vector that are at right angles to each other, obtained by breaking down a vector into horizontal and vertical parts.
projectile motionA special case of two-dimensional motion in which an object experiences zero acceleration in one dimension and constant, nonzero acceleration in the perpendicular dimension.
resultantThe single vector that represents the combined effect of two or more perpendicular component vectors.
trigonometric functionsMathematical functions (sine, cosine, tangent) used to calculate the perpendicular components of a vector based on its magnitude and angle.
two-dimensional motionMotion of an object that occurs in two perpendicular directions simultaneously.
vectorA quantity that has both magnitude and direction, which can be represented as the sum of perpendicular components.

📚Unit 2 – Force and Translational Dynamics

2.1 Systems and Center of Mass

TermDefinition
center of massThe point in a system where all the mass can be considered to be concentrated for the purpose of analyzing motion and forces.
constituent objectsThe individual objects that make up a system.
constituent partsThe individual objects or components that make up a larger system.
energy transferThe movement of energy from one part of a system to another or between a system and its environment.
internal structureThe arrangement and organization of constituent parts within a system that affects how the system behaves and is analyzed.
lines of symmetryImaginary lines about which a system's mass is evenly distributed, and where the center of mass is located for symmetrical objects.
macroscopic systemA system large enough to be observed and analyzed at the scale of everyday objects, rather than at the atomic or molecular level.
mass transferThe movement of matter from one part of a system to another or between a system and its environment.
symmetrical mass distributionAn arrangement of mass in a system where the mass is evenly distributed about one or more lines or planes of symmetry.
systemA collection of objects and their interactions that are studied together as a single unit.
system propertiesThe characteristics and behaviors of a system that are determined by the interactions between objects within it.

2.2 Forces and Free-Body Diagrams

TermDefinition
center of massThe point in a system where all the mass can be considered to be concentrated for the purpose of analyzing motion and forces.
contact forcesForces that result from two objects or systems physically touching each other, arising from interatomic electric forces.
coordinate systemA reference framework used to resolve vectors into their perpendicular components, typically using horizontal and vertical axes.
forceA vector quantity that describes the interaction between two objects or systems.
free-body diagramA visual representation that shows all forces exerted on an object or system, with each force drawn as a vector originating from the object's center of mass.
interactionThe mutual influence or effect between two objects or systems, which produces a force.
interatomic electric forcesThe electromagnetic forces between atoms that produce the macroscopic effects observed as contact forces.
net forceThe vector sum of all forces acting on an object or system.
systemA collection of objects and their interactions that are studied together as a single unit.
vectorA quantity that has both magnitude and direction, which can be represented as the sum of perpendicular components.

2.3 Newton's Third Law

TermDefinition
center of massThe point in a system where all the mass can be considered to be concentrated for the purpose of analyzing motion and forces.
ideal pulleyA theoretical pulley with negligible mass that rotates about its center of mass with negligible friction.
ideal stringA theoretical string with negligible mass that does not stretch under tension and has uniform tension throughout its length.
internal forcesForces that objects within a system exert on each other, which do not affect the motion of the system's center of mass.
Newton's third lawThe principle that forces always occur in equal and opposite pairs: if object A exerts a force on object B, then object B exerts an equal and opposite force on object A.
paired forcesTwo equal and opposite forces that result from the interaction between two objects, as described by Newton's third law.
tensionThe macroscopic net force that segments of a string, cable, chain, or similar system exert on each other in response to an external force.

2.4 Newton's First Law

TermDefinition
balanced forcesForces acting on a system that result in a net force of zero in a particular dimension.
inertial reference frameA reference frame in which Newton's laws of motion apply; a frame that is either at rest or moving at constant velocity.
net forceThe vector sum of all forces acting on an object or system.
Newton's first lawThe principle stating that if the net force exerted on a system is zero, the velocity of that system will remain constant.
translational equilibriumA state in which an object's linear velocity remains constant because the net force exerted on it is zero.
unbalanced forcesA configuration of forces where the net force exerted on a system is not equal to zero, resulting in acceleration.
vector sumThe result of adding two or more vectors together, taking into account both magnitude and direction.
velocityA vector quantity that describes both the speed and direction of an object's motion.

2.5 Newton's Second Law

TermDefinition
accelerationThe rate of change of velocity with respect to time.
center of massThe point in a system where all the mass can be considered to be concentrated for the purpose of analyzing motion and forces.
net forceThe vector sum of all forces acting on an object or system.
Newton's second law of motionThe principle stating that the acceleration of a system's center of mass is proportional to the net force exerted on it and occurs in the same direction as that force.
nonzero net external forceA net force applied to a system from outside that is not equal to zero, causing the system's velocity to change.
unbalanced forcesA configuration of forces where the net force exerted on a system is not equal to zero, resulting in acceleration.
velocityA vector quantity that describes both the speed and direction of an object's motion.

2.7 Kinetic and Static Friction

TermDefinition
coefficient of kinetic frictionA dimensionless constant (μₖ) that represents the ratio of kinetic friction force to the normal force between two surfaces moving relative to each other.
coefficient of static frictionA dimensionless constant (μₛ) that represents the ratio of the maximum static friction force to the normal force between two surfaces.
frictionA nonconservative force that opposes motion and dissipates mechanical energy.
kinetic frictionThe friction force that acts between two surfaces when they are in contact and moving relative to each other.
normal forceThe perpendicular component of the force exerted on an object by a surface, directed away from the surface.
slippingA situation in which two surfaces in contact are moving relative to each other.
static frictionA friction force that acts between two surfaces in contact that are not moving relative to each other, preventing an object from slipping or sliding.

2.9 Circular Motion

TermDefinition
banked surfaceAn inclined surface on which an object travels in a circular path, where normal force and friction components contribute to centripetal acceleration.
centripetal accelerationThe component of an object's acceleration directed toward the center of its circular path.
circular orbitThe path of a satellite moving around a central body at a constant distance, where gravitational force provides the centripetal force needed to maintain the circular path.
circular pathThe trajectory followed by an object moving in a circle around a fixed center point.
conical pendulumA pendulum that moves in a horizontal circle, with tension providing a component of the centripetal force.
frequencyThe number of complete oscillations or cycles of simple harmonic motion that occur per unit time, typically measured in hertz (Hz).
gravitational attractionThe force of gravity exerted by a central body on a satellite, which provides the centripetal force necessary for circular orbital motion.
gravitational forceThe attractive force due to mass, which can serve as the sole source of centripetal acceleration at the top of a vertical circular loop.
Kepler's third lawA principle stating that the square of a satellite's orbital period is proportional to the cube of its orbital radius, expressed as T² = (4π²/GM)R³.
net accelerationThe vector sum of centripetal acceleration and tangential acceleration for an object moving in a circle.
normal forceThe perpendicular component of the force exerted on an object by a surface, directed away from the surface.
orbital periodThe time it takes for a satellite to complete one full orbit around a central body.
orbital radiusThe distance from the center of a central body to a satellite in circular orbit.
periodThe time required for an object to complete one full circular path, rotation, or cycle.
radiusThe distance from the center of a circular path to the object traveling on that path.
static frictionA friction force that acts between two surfaces in contact that are not moving relative to each other, preventing an object from slipping or sliding.
tangential accelerationThe component of linear acceleration directed along the tangent to the circular path of a rotating point, related to angular acceleration by a_T = rα.
tangential speedThe instantaneous speed of an object moving along a circular path, directed tangent to the circle.
tensionThe macroscopic net force that segments of a string, cable, chain, or similar system exert on each other in response to an external force.
uniform circular motionMotion of an object traveling in a circular path at constant speed.
vertical circular loopA circular path oriented vertically, where an object must maintain a minimum speed at the top to continue circular motion.

📚Unit 3 – Work, Energy, and Power

3.1 Translational Kinetic Energy

TermDefinition
coordinate systemA reference framework used to resolve vectors into their perpendicular components, typically using horizontal and vertical axes.
scalarA physical quantity that has magnitude only, without direction.
translational kinetic energyThe kinetic energy associated with the linear motion of an object's center of mass.

3.2 Work

TermDefinition
air resistanceA nonconservative force exerted by air on a moving object that opposes its motion.
center of massThe point in a system where all the mass can be considered to be concentrated for the purpose of analyzing motion and forces.
conservative forcesForces for which the work done is independent of the path taken, and energy can be stored as potential energy (such as gravitational or elastic forces).
displacementA vector quantity representing the change in position of an object from its initial to final location.
frictionA nonconservative force that opposes motion and dissipates mechanical energy.
kinetic energyThe energy possessed by an object due to its motion, equal to one-half the product of its mass and the square of its velocity.
mechanical energyThe sum of a system's kinetic and potential energies.
net workThe sum of all work done by all forces exerted on an object.
nonconservative forceA force for which the work done is path-dependent, such as friction or air resistance.
potential energyThe energy stored in a system due to the relative positions or configurations of objects that interact via conservative forces.
scalarA physical quantity that has magnitude only, without direction.
workThe amount of energy transferred into or out of a system by a force exerted on that system over a distance.
work-energy theoremThe principle stating that the change in an object's kinetic energy equals the net work done by all forces exerted on the object.

3.3 Potential Energy

TermDefinition
conservative forcesForces for which the work done is independent of the path taken, and energy can be stored as potential energy (such as gravitational or elastic forces).
elastic potential energyThe potential energy stored in a spring or elastic object due to its deformation from equilibrium length.
equilibrium lengthThe natural length of a spring when no external forces are applied to stretch or compress it.
gravitational fieldThe region of space around a mass where gravitational force is exerted on other masses.
gravitational potential energyThe potential energy of a system due to the gravitational interaction between two masses separated by a distance.
ideal springA theoretical spring that obeys Hooke's law and stores elastic potential energy proportional to the square of its displacement.
potential energyThe energy stored in a system due to the relative positions or configurations of objects that interact via conservative forces.
scalarA physical quantity that has magnitude only, without direction.
systemA collection of objects and their interactions that are studied together as a single unit.
zero potential energyA reference point chosen by an observer to simplify analysis of a system's potential energy.

3.4 Conservation of Energy

TermDefinition
conservation of mechanical energyThe principle that the total mechanical energy of a system remains constant when only conservative forces act on it, or changes by an amount equal to energy transferred into or out of the system.
conservative forcesForces for which the work done is independent of the path taken, and energy can be stored as potential energy (such as gravitational or elastic forces).
energyThe capacity to do work or cause change; a conserved quantity that can be transferred between a system and its environment.
energy transferThe movement of energy from one part of a system to another or between a system and its environment.
environmentEverything outside the defined system; the region with which the system can exchange energy through work or other interactions.
kinetic energyThe energy possessed by an object due to its motion, equal to one-half the product of its mass and the square of its velocity.
mechanical energyThe sum of a system's kinetic and potential energies.
nonconservative interactionsInteractions within a system, such as friction or air resistance, that dissipate mechanical energy and cause the total mechanical energy to decrease.
potential energyThe energy stored in a system due to the relative positions or configurations of objects that interact via conservative forces.
systemA collection of objects and their interactions that are studied together as a single unit.
workThe amount of energy transferred into or out of a system by a force exerted on that system over a distance.

3.5 Power

TermDefinition
average powerThe total amount of energy transferred or converted divided by the time interval over which the transfer or conversion occurs.
energy transferThe movement of energy from one part of a system to another or between a system and its environment.
instantaneous powerThe rate of energy transfer at a specific moment in time, calculated as the component of force parallel to velocity multiplied by that velocity.
powerThe rate at which energy is transferred into, out of, or converted within a system with respect to time.
workThe amount of energy transferred into or out of a system by a force exerted on that system over a distance.

📚Unit 4 – Linear Momentum

4.1 Linear Momentum

TermDefinition
collisionAn interaction between objects where the forces exerted between them are much larger than external forces, allowing analysis of initial and final states.
explosionAn interaction in which internal forces within a system move objects apart.
momentumA vector quantity that describes the motion of an object, equal to mass times velocity, with direction matching the velocity.
object modelA simplification in physics where an object is treated as a single point with properties like mass and charge, ignoring size, shape, and internal structure.
systemA collection of objects and their interactions that are studied together as a single unit.
vectorA quantity that has both magnitude and direction, which can be represented as the sum of perpendicular components.

4.3 Conservation of Linear Momentum

TermDefinition
center of massThe point in a system where all the mass can be considered to be concentrated for the purpose of analyzing motion and forces.
center-of-mass velocityThe velocity of the center of mass of a system, calculated as the total momentum divided by the total mass.
collisionAn interaction between objects where the forces exerted between them are much larger than external forces, allowing analysis of initial and final states.
conservation of momentumThe principle that the total momentum of a system remains constant when no net external force acts on the system.
explosionAn interaction in which internal forces within a system move objects apart.
impulseThe change in momentum of an object, equal to the force applied multiplied by the time interval over which it acts.
momentumA vector quantity that describes the motion of an object, equal to mass times velocity, with direction matching the velocity.
net external forceThe vector sum of all forces acting on a system from outside the system.
Newton's third lawThe principle that forces always occur in equal and opposite pairs: if object A exerts a force on object B, then object B exerts an equal and opposite force on object A.
systemA collection of objects and their interactions that are studied together as a single unit.

4.4 Elastic and Inelastic Collisions

TermDefinition
elastic collisionA collision between objects in which the total kinetic energy of the system is conserved, remaining equal before and after the collision.
inelastic collisionA collision between objects in which the total kinetic energy of the system decreases, with some kinetic energy transformed into other forms of energy by nonconservative forces.
kinetic energyThe energy possessed by an object due to its motion, equal to one-half the product of its mass and the square of its velocity.
nonconservative forceA force for which the work done is path-dependent, such as friction or air resistance.
perfectly inelastic collisionA collision in which the colliding objects stick together and move with the same velocity after the collision.

📚Unit 5 – Torque and Rotational Dynamics

5.1 Rotational Kinematics

TermDefinition
angular accelerationThe rate of change of angular velocity with respect to time.
angular displacementThe measurement of the angle, in radians, through which a point on a rigid system rotates about a specified axis.
angular velocityThe rate at which an object or system rotates, measured as the change in angular position per unit time.
axis of rotationThe fixed line about which a system rotates.
center of massThe point in a system where all the mass can be considered to be concentrated for the purpose of analyzing motion and forces.
constant angular accelerationA situation in which angular velocity changes at a uniform rate over time.
rigid systemA system that holds its shape but in which different points on the system move in different directions during rotation.

5.2 Connecting Linear and Rotational Motion

TermDefinition
angular accelerationThe rate of change of angular velocity with respect to time.
angular displacementThe measurement of the angle, in radians, through which a point on a rigid system rotates about a specified axis.
angular velocityThe rate at which an object or system rotates, measured as the change in angular position per unit time.
axis of rotationThe fixed line about which a system rotates.
linear motionMotion along a straight path, characterized by displacement, velocity, and acceleration in one dimension.
rigid systemA system that holds its shape but in which different points on the system move in different directions during rotation.
rotational motionMotion of an object or system rotating about a fixed axis, characterized by angular displacement, angular velocity, and angular acceleration.
tangential accelerationThe component of linear acceleration directed along the tangent to the circular path of a rotating point, related to angular acceleration by a_T = rα.
tangential velocityThe linear velocity of a point on a rotating system directed along the tangent to its circular path, related to angular velocity by v = rω.

5.3 Torque

TermDefinition
axis of rotationThe fixed line about which a system rotates.
force component perpendicularThe portion of an applied force that acts at a right angle to the position vector from the axis of rotation.
force diagramA diagram used to represent and analyze the forces and torques exerted on a rigid system, showing the magnitude, direction, and point of application of each force relative to the axis of rotation.
free-body diagramA visual representation that shows all forces exerted on an object or system, with each force drawn as a vector originating from the object's center of mass.
lever armThe perpendicular distance from the axis of rotation to the line of action of an applied force.
line of actionThe straight line along which a force acts, extending infinitely in both directions.
perpendicular forceThe component of a force that is perpendicular to the position vector, which directly contributes to torque production.
position vectorA vector drawn from the axis of rotation to the point where a force is applied on a rigid system.
rigid systemA system that holds its shape but in which different points on the system move in different directions during rotation.
torqueA measure of the rotational effect of a force on a rigid system, calculated as the product of the force and its perpendicular distance from the axis of rotation.

5.4 Rotational Inertia

TermDefinition
axis of rotationThe fixed line about which a system rotates.
center of massThe point in a system where all the mass can be considered to be concentrated for the purpose of analyzing motion and forces.
mass distributionThe spatial arrangement of mass within a system relative to a reference point or axis, which affects the system's rotational inertia.
parallel axis theoremA theorem that relates the rotational inertia of a rigid system about any axis parallel to an axis through its center of mass, expressed as I' = I_cm + Md².
perpendicular distanceThe shortest distance from a point or object to the axis of rotation, measured at a right angle to the axis.
rigid systemA system that holds its shape but in which different points on the system move in different directions during rotation.
rotational inertiaA measure of a rigid system's resistance to changes in its rotational motion, dependent on both the mass of the system and how that mass is distributed relative to the axis of rotation.

5.5 Rotational Equilibrium and Newton's First Law in Rotational Form

TermDefinition
angular velocityThe rate at which an object or system rotates, measured as the change in angular position per unit time.
force diagramA diagram used to represent and analyze the forces and torques exerted on a rigid system, showing the magnitude, direction, and point of application of each force relative to the axis of rotation.
free-body diagramA visual representation that shows all forces exerted on an object or system, with each force drawn as a vector originating from the object's center of mass.
net torqueThe sum of all torques acting on an object or system, which determines whether angular velocity will change.
rigid systemA system that holds its shape but in which different points on the system move in different directions during rotation.
rotational equilibriumA state in which a system maintains constant angular velocity because the net torque exerted on it is zero.
torqueA measure of the rotational effect of a force on a rigid system, calculated as the product of the force and its perpendicular distance from the axis of rotation.
translational equilibriumA state in which an object's linear velocity remains constant because the net force exerted on it is zero.

5.6 Newton's Second Law in Rotational Form

TermDefinition
angular accelerationThe rate of change of angular velocity with respect to time.
angular velocityThe rate at which an object or system rotates, measured as the change in angular position per unit time.
net torqueThe sum of all torques acting on an object or system, which determines whether angular velocity will change.
rigid systemA system that holds its shape but in which different points on the system move in different directions during rotation.
rotational inertiaA measure of a rigid system's resistance to changes in its rotational motion, dependent on both the mass of the system and how that mass is distributed relative to the axis of rotation.

📚Unit 6 – Rotating Systems: Energy & Momentum

6.1 Rotational Kinetic Energy

TermDefinition
angular velocityThe rate at which an object or system rotates, measured as the change in angular position per unit time.
center of massThe point in a system where all the mass can be considered to be concentrated for the purpose of analyzing motion and forces.
rigid systemA system that holds its shape but in which different points on the system move in different directions during rotation.
rotational inertiaA measure of a rigid system's resistance to changes in its rotational motion, dependent on both the mass of the system and how that mass is distributed relative to the axis of rotation.
rotational kinetic energyThe kinetic energy possessed by a rigid system due to its rotation about an axis, calculated as K = 1/2 I ω².
scalarA physical quantity that has magnitude only, without direction.
translational kinetic energyThe kinetic energy associated with the linear motion of an object's center of mass.

6.2 Torque and Work

TermDefinition
angular displacementThe measurement of the angle, in radians, through which a point on a rigid system rotates about a specified axis.
angular positionThe rotational location of an object, typically measured as an angle from a reference direction.
rigid systemA system that holds its shape but in which different points on the system move in different directions during rotation.
torqueA measure of the rotational effect of a force on a rigid system, calculated as the product of the force and its perpendicular distance from the axis of rotation.
workThe amount of energy transferred into or out of a system by a force exerted on that system over a distance.

6.3 Angular Momentum and Angular Impulse

TermDefinition
angular accelerationThe rate of change of angular velocity with respect to time.
angular impulseThe product of the torque exerted on an object or rigid system and the time interval during which the torque is exerted, calculated as τΔt.
angular momentumA measure of the rotational motion of an object or system, calculated as the product of moment of inertia and angular velocity, or as the product of mass, velocity, and perpendicular distance from a reference point.
angular velocityThe rate at which an object or system rotates, measured as the change in angular position per unit time.
impulse-momentum theoremA principle relating the impulse applied to an object to its change in momentum; in rotational form, it relates angular impulse to change in angular momentum.
Newton's second law of motionThe principle stating that the acceleration of a system's center of mass is proportional to the net force exerted on it and occurs in the same direction as that force.
radial distanceThe perpendicular distance from a reference point or axis to an object.
rigid systemA system that holds its shape but in which different points on the system move in different directions during rotation.
rotational inertiaA measure of a rigid system's resistance to changes in its rotational motion, dependent on both the mass of the system and how that mass is distributed relative to the axis of rotation.
torqueA measure of the rotational effect of a force on a rigid system, calculated as the product of the force and its perpendicular distance from the axis of rotation.

6.4 Conservation of Angular Momentum

TermDefinition
angular impulseThe product of the torque exerted on an object or rigid system and the time interval during which the torque is exerted, calculated as τΔt.
angular momentumA measure of the rotational motion of an object or system, calculated as the product of moment of inertia and angular velocity, or as the product of mass, velocity, and perpendicular distance from a reference point.
angular momentum transferThe process by which angular momentum is exchanged between a system and its environment when net external torque is nonzero.
angular speedThe rate at which an object or system rotates about a rotational axis, measured in radians per unit time.
axis of rotationThe fixed line about which a system rotates.
conservation of angular momentumThe principle that the total angular momentum of a system remains constant when the net external torque is zero.
net external torqueThe total rotational force applied to a system from outside sources.
nonrigid systemA system whose shape or configuration can change, allowing mass to move closer to or further from the rotational axis.
rigid systemA system that holds its shape but in which different points on the system move in different directions during rotation.
systemA collection of objects and their interactions that are studied together as a single unit.

6.5 Rolling

TermDefinition
angular accelerationThe rate of change of angular velocity with respect to time.
angular displacementThe measurement of the angle, in radians, through which a point on a rigid system rotates about a specified axis.
angular velocityThe rate at which an object or system rotates, measured as the change in angular position per unit time.
center of massThe point in a system where all the mass can be considered to be concentrated for the purpose of analyzing motion and forces.
energy dissipationThe process by which mechanical energy is converted to other forms (such as heat) and removed from a system.
frictionA nonconservative force that opposes motion and dissipates mechanical energy.
kinetic energyThe energy possessed by an object due to its motion, equal to one-half the product of its mass and the square of its velocity.
kinetic frictionThe friction force that acts between two surfaces when they are in contact and moving relative to each other.
rollingMotion of a system that combines both translational motion of its center of mass and rotational motion about its center of mass.
rolling without slippingMotion of a rolling object where the contact point with the surface has zero velocity, meaning the translational and rotational motions are related by the constraint that the distance traveled by the center of mass equals the arc length rotated.
rotational kinetic energyThe kinetic energy possessed by a rigid system due to its rotation about an axis, calculated as K = 1/2 I ω².
rotational motionMotion of an object or system rotating about a fixed axis, characterized by angular displacement, angular velocity, and angular acceleration.
slippingA situation in which two surfaces in contact are moving relative to each other.
translational kinetic energyThe kinetic energy associated with the linear motion of an object's center of mass.
translational motionMotion of an object's center of mass through space, described by the displacement, velocity, and acceleration of the center of mass.

6.6 Motion of Orbiting Satellites

TermDefinition
angular momentumA measure of the rotational motion of an object or system, calculated as the product of moment of inertia and angular velocity, or as the product of mass, velocity, and perpendicular distance from a reference point.
circular orbitsOrbital paths where a satellite maintains a constant distance from the central object, resulting in constant speed and energy.
conservation lawsPhysical principles stating that certain quantities (such as energy and angular momentum) remain constant in an isolated system.
elliptical orbitsOrbital paths where a satellite's distance from the central object varies, causing changes in speed and kinetic energy while total mechanical energy remains constant.
escape velocityThe minimum velocity required for a satellite to escape the gravitational pull of a central object, achieved when the system's total mechanical energy equals zero.
gravitational forceThe attractive force due to mass, which can serve as the sole source of centripetal acceleration at the top of a vertical circular loop.
gravitational potential energyThe potential energy of a system due to the gravitational interaction between two masses separated by a distance.
kinetic energyThe energy possessed by an object due to its motion, equal to one-half the product of its mass and the square of its velocity.
total mechanical energyThe sum of kinetic and potential energy in a system; remains constant in both circular and elliptical orbits.

📚Unit 7 – Oscillations

7.1 Defining Simple Harmonic Motion (SHM)

TermDefinition
angular displacementThe measurement of the angle, in radians, through which a point on a rigid system rotates about a specified axis.
displacementA vector quantity representing the change in position of an object from its initial to final location.
equilibrium positionThe central position around which an object oscillates in SHM, where the net force is zero.
periodic motionMotion that repeats at regular time intervals.
restoring forceA force exerted on an object in a direction opposite to its displacement from an equilibrium position, acting to return the object to equilibrium.
restoring torqueA rotational force that acts in a direction opposite to angular displacement, returning an object toward its equilibrium orientation.
simple harmonic motionA special case of periodic motion in which a restoring force proportional to displacement causes an object to oscillate about an equilibrium position.

7.2 Frequency and Period of SHM

TermDefinition
frequencyThe number of complete oscillations or cycles of simple harmonic motion that occur per unit time, typically measured in hertz (Hz).
object-ideal-spring oscillatorA system consisting of a mass attached to an ideal spring that undergoes simple harmonic motion.
periodThe time required for an object to complete one full circular path, rotation, or cycle.
simple harmonic motionA special case of periodic motion in which a restoring force proportional to displacement causes an object to oscillate about an equilibrium position.
simple pendulumA mass suspended from a fixed point by a string or rod of negligible mass that swings back and forth in simple harmonic motion.

7.3 Representing and Analyzing SHM

TermDefinition
accelerationThe rate of change of velocity with respect to time.
amplitudeThe maximum displacement of an oscillating system from its equilibrium position; determines the maximum potential energy and total energy of the system.
displacementA vector quantity representing the change in position of an object from its initial to final location.
equilibrium positionThe central position around which an object oscillates in SHM, where the net force is zero.
extremaThe maximum or minimum values of displacement, velocity, or acceleration in SHM.
frequencyThe number of complete oscillations or cycles of simple harmonic motion that occur per unit time, typically measured in hertz (Hz).
harmonic motionRepetitive motion characterized by displacement, velocity, and acceleration that vary periodically with time.
periodThe time required for an object to complete one full circular path, rotation, or cycle.
velocityA vector quantity that describes both the speed and direction of an object's motion.

7.4 Energy of Simple Harmonic Oscillators

TermDefinition
amplitudeThe maximum displacement of an oscillating system from its equilibrium position; determines the maximum potential energy and total energy of the system.
conservation of energyThe principle that the total mechanical energy of a system remains constant when only conservative forces act on it.
kinetic energyThe energy possessed by an object due to its motion, equal to one-half the product of its mass and the square of its velocity.
mechanical energyThe sum of a system's kinetic and potential energies.
potential energyThe energy stored in a system due to the relative positions or configurations of objects that interact via conservative forces.
simple harmonic motionA special case of periodic motion in which a restoring force proportional to displacement causes an object to oscillate about an equilibrium position.
total mechanical energyThe sum of kinetic and potential energy in a system; remains constant in both circular and elliptical orbits.

📚Unit 8 – Fluids

8.1 Internal Structure and Density

TermDefinition
densityA measure of how much mass is contained in a given volume of a substance, calculated as the ratio of mass to volume.
fluidA substance that can flow and conform to the shape of its container, including liquids and gases.
gasA state of matter with no fixed shape or volume, where atoms and molecules have minimal interactions and move freely.
ideal fluidA theoretical fluid that is incompressible and has no viscosity, used as a model for analyzing fluid behavior.
incompressibleA property of a fluid that cannot be reduced in volume by the application of pressure.
liquidA state of matter with a fixed volume but no fixed shape, where atoms and molecules have moderate interactions.
massThe amount of matter in an object, typically measured in kilograms.
solidA state of matter with a fixed shape and fixed volume, where atoms and molecules are tightly bonded.
viscosityA measure of a fluid's resistance to flow, or its internal friction.
volumeThe amount of space occupied by a substance or object, typically measured in cubic meters or liters.

8.2 Pressure

TermDefinition
absolute pressureThe total pressure at a given point in a fluid, equal to the sum of a reference pressure and the gauge pressure.
atmospheric pressureThe pressure exerted by the weight of the atmosphere, commonly used as a reference pressure (Patm).
fluidA substance that can flow and conform to the shape of its container, including liquids and gases.
gauge pressureThe pressure of a fluid measured relative to a reference pressure, typically atmospheric pressure, calculated as the difference between absolute pressure and reference pressure.
incompressible fluidA fluid whose density remains essentially constant during flow, regardless of pressure changes.
perpendicular force componentThe component of a force that acts at a right angle to a surface.
pressureThe magnitude of the perpendicular force component exerted per unit area over a given surface area.
reference pressureA baseline pressure used as a starting point for measuring gauge pressure, such as atmospheric pressure (P0).
scalarA physical quantity that has magnitude only, without direction.

8.3 Fluids and Newton's Laws

TermDefinition
buoyant forceThe net upward force exerted on an object by a fluid as a result of pressure differences across the object's surface.
constituent particlesThe individual molecules or atoms that make up a fluid.
external forcesForces applied to a fluid from outside sources that affect its motion and behavior.
fluidA substance that can flow and conform to the shape of its container, including liquids and gases.
fluid displacedThe volume of fluid that is pushed aside or occupies the space taken up by a submerged or partially submerged object.
fluid velocityThe speed and direction of fluid motion, which changes in response to internal particle interactions and external forces.
internal interactionsThe forces and interactions between particles within a fluid that contribute to its macroscopic behavior.
macroscopic behaviorThe large-scale, observable behavior of a fluid as a whole, resulting from the combined effects of internal particle interactions and external forces.
Newton's lawsThe three fundamental laws of motion that describe how forces affect the motion of objects, including particles within a fluid.
weight of fluid displacedThe gravitational force exerted on the volume of fluid that an object displaces, which equals the magnitude of the buoyant force.

8.4 Fluids and Conservation Laws

TermDefinition
Bernoulli's equationA mathematical equation describing the conservation of mechanical energy in fluid flow, relating pressure, gravitational potential energy, and kinetic energy at two points in a fluid.
conservation of mechanical energyThe principle that the total mechanical energy of a system remains constant when only conservative forces act on it, or changes by an amount equal to energy transferred into or out of the system.
continuity equationThe mathematical relationship stating that the mass flow rate of an incompressible fluid remains constant throughout a tube, expressed as A₁v₁ = A₂v₂.
cross-sectional areaThe area of a surface perpendicular to the direction of fluid flow through a tube or channel.
flow rateThe volume or mass of fluid passing through a cross-sectional area per unit time.
fluid flowThe motion of a fluid from one location to another, driven by differences in energy within the fluid-Earth system.
gravitational potential energyThe potential energy of a system due to the gravitational interaction between two masses separated by a distance.
incompressible fluidA fluid whose density remains essentially constant during flow, regardless of pressure changes.
kinetic energyThe energy possessed by an object due to its motion, equal to one-half the product of its mass and the square of its velocity.
mass conservationThe principle that the total mass of a system remains constant over time, with no mass created or destroyed.
pressureThe magnitude of the perpendicular force component exerted per unit area over a given surface area.
pressure differenceThe variation in pressure between two locations that causes a fluid to flow from higher to lower pressure.
Torricelli's theoremA principle stating that the speed of a fluid exiting an opening is related to the vertical distance between the opening and the fluid's surface, derived from conservation of energy.

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