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📚AP Physics 1 Unit 5 Vocabulary

46 essential vocabulary terms and definitions for Unit 5 – Torque and Rotational Dynamics

Study Unit 5
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📚Unit 5 – Torque and Rotational Dynamics
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📚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.