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Unit 6: Energy and Momentum of Rotating Systems

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What is the rotational analogue of linear momentum, and how does an angular impulse change it?

Topic 6.3 Angular Momentum and Angular Impulse: define angular momentum and relate the angular impulse from a torque to the change in angular momentum.
A focused answer to AP Physics 1 Topic 6.3, covering angular momentum L = I omega as the rotational analogue of linear momentum, angular impulse as torque times time, the angular impulse-momentum theorem, and point-particle angular momentum, with full worked examples.
11 min answer →

When is the angular momentum of a system conserved, and how does that explain a spinning skater speeding up?

Topic 6.4 Conservation of Angular Momentum: apply conservation of angular momentum to systems with no net external torque, including changes in rotational inertia.
A focused answer to AP Physics 1 Topic 6.4, covering the conservation of angular momentum when no net external torque acts, the I omega = constant relation, the spinning-skater effect, rotational collisions, and why kinetic energy can change while angular momentum is conserved, with full worked examples.
11 min answer →

What keeps a satellite in orbit, and how do energy and angular momentum behave in circular and elliptical orbits?

Topic 6.6 Motion of Orbiting Satellites: analyze circular and elliptical orbits using gravity as the centripetal force, gravitational potential energy, and conservation of energy and angular momentum.
A focused answer to AP Physics 1 Topic 6.6, covering orbital motion with gravity as the centripetal force, the orbital speed of a circular orbit, gravitational potential energy, and how mechanical energy and angular momentum are conserved over an elliptical orbit, with full worked examples.
11 min answer →

What is the condition for rolling without slipping, and how do energy methods predict which object reaches the bottom of a ramp first?

Topic 6.5 Rolling: analyze objects that roll without slipping using the v = R omega condition and the partition of energy between translation and rotation.
A focused answer to AP Physics 1 Topic 6.5, covering rolling without slipping, the constraint v_cm = R omega, the total kinetic energy of a rolling object, why mass distribution decides the race down a ramp, and the role of static friction, with full worked examples.
11 min answer →

How does a rotating object store kinetic energy, and how does that energy depend on its rotational inertia and angular velocity?

Topic 6.1 Rotational Kinetic Energy: define the kinetic energy of a rotating rigid body and relate it to rotational inertia and angular velocity.
A focused answer to AP Physics 1 Topic 6.1, covering rotational kinetic energy as the rotational analogue of translational kinetic energy, the relation K = half I omega squared, how it depends on rotational inertia and angular velocity, and the total kinetic energy of a rolling object, with full worked examples.
10 min answer →

How does a torque do work on a rotating object, and how is that work related to the change in its rotational kinetic energy?

Topic 6.2 Torque and Work: calculate the work done by a torque through an angular displacement and apply the work-energy theorem to rotation.
A focused answer to AP Physics 1 Topic 6.2, covering the work done by a torque as W = tau times angular displacement, the rotational work-energy theorem, rotational power P = tau omega, and how these mirror the translational versions, with full worked examples.
10 min answer →