What is AP Physics 1 Unit 6 about?
Unit 6 Energy and Momentum of Rotating Systems is a current AP Physics 1 unit with an official multiple-choice weighting of 5–8%. This hub maps every topic in the unit to focused lessons, examples, representations and practice.
- Official unit weighting: 5–8% of the MCQ section.
- Every official topic in this unit has its own lesson and 42-MCQ/4-FRQ practice bank.
- Use the unit hub for sequencing; use the child topic pages for exact definitions and worked reasoning.
Unit 6 · Energy and Momentum of Rotating Systems
Unit 6 applies energy and angular-momentum ideas to rotating and rolling systems and to orbiting satellites.
Unit 6 topic map
Use the unit hub to understand how the ideas connect; use each topic lesson for definitions, real examples, equations, worked reasoning, misconceptions and focused practice.
Rotational Kinetic Energy
Rotational kinetic energy is energy associated with rotation of a rigid body and depends on its rotational inertia and angular speed.
Torque and Work
Work in rotational motion transfers energy when a torque acts through an angular displacement; rotational work changes rotational kinetic energy analogously to translational work.
Angular Momentum and Angular Impulse
Angular momentum describes rotational motion about an axis, while angular impulse—the accumulated external torque over time—equals the change in angular momentum.
Conservation of Angular Momentum
Angular momentum of a system about an axis is conserved when the net external angular impulse about that axis is zero or negligible.
Rolling
Rolling motion combines translation of an object’s center of mass with rotation about its center; rolling without slipping imposes a geometric constraint between linear and angular motion.
Motion of Orbiting Satellites
An orbiting satellite follows a gravitationally bound path around a central body. Circular orbits use gravity as the centripetal force, while elliptical orbits continually exchange kinetic and gravitational potential energy as orbital radius changes.