---
title: "AP Physics C: Mechanics Unit 6 Review: Energy & Momentum"
description: "AP Physics C: Mechanics Unit 6 covers Rotational Kinetic Energy and Torque and Work. Study guides, practice questions, and key terms for every topic."
canonical: "https://fiveable.me/ap-physics-c-mechanics/unit-6"
type: "unit"
subject: "AP Physics C: Mechanics"
unit: "Unit 6 – Rotating Systems: Energy & Momentum"
---

# AP Physics C: Mechanics Unit 6 Review: Energy & Momentum

## Overview

Unit 6 extends the energy and momentum frameworks from Units 3 and 4 into rotating systems. You will calculate rotational kinetic energy using K_rot = 1/2 I omega^2, find work done by torques through angular displacements, define and apply angular momentum in both L = I omega and L = r x p forms, use conservation of angular momentum when net external torque is zero, analyze rolling without slipping using v_cm = r omega, and apply conservation laws to circular and elliptical satellite orbits.

## AP CED Alignment

This unit hub is organized around AP Course and Exam Description topics, skills, and exam task types when they are available in the source data.
- Topic 6.1: Rotational Kinetic Energy
- Topic 6.2: Torque and Work
- Topic 6.3: Angular Momentum and Angular Impulse
- Topic 6.4: Conservation of Angular Momentum
- Topic 6.5: Rolling
- Topic 6.6: Motion of Orbiting Satellites
- Topic 6.5: Rolling Motion
- Practice 3: Scientific Questioning and Argumentation
- FRQ 4 – Qualitative/Quantitative Translation
- FRQ 2 – Translation Between Representations
- FRQ 3 – Experimental Design

## Topics

- [Topic 6.1: Rotational Kinetic Energy](/ap-physics-c-mechanics/unit-6/1-rotational-kinetic-energy/study-guide/Y5pLDWQTbxH05tCF): Defines K_rot = 1/2 I omega^2 and establishes that total kinetic energy is the sum of translational and rotational contributions. Introduces the scalar nature of rotational kinetic energy and common moment-of-inertia values.
- [Topic 6.2: Torque and Work](/ap-physics-c-mechanics/unit-6/2-torque-and-work/study-guide/IDr6scmUlLJQ3Uub): Develops W = integral tau d theta as the rotational analog of linear work, including the graphical interpretation as area under a tau-versus-theta curve and the rotational work-energy theorem.
- [Topic 6.3: Angular Momentum and Angular Impulse](/ap-physics-c-mechanics/unit-6/3-angular-momentum-and-angular-impulse/study-guide/3jrKVVLAakxu58LX): Introduces L = I omega and L = r x p, defines angular impulse as the integral of tau dt, and connects them through the rotational impulse-momentum theorem delta L = integral tau dt.
- [Topic 6.4: Conservation of Angular Momentum](/ap-physics-c-mechanics/unit-6/4-conservation-of-angular-momentum/study-guide/9JJXeFccr7Xo7FHS): Establishes that total angular momentum is conserved when net external torque is zero, explains how nonrigid systems change omega by redistributing mass, and emphasizes system boundary selection.
- [Topic 6.5: Rolling](/ap-physics-c-mechanics/unit-6/5-kinetic-energy-of-a-system-with-translational-and-rotational-motion/study-guide/tpS8vdLgJ6AQpm2V): Applies the no-slip constraint v_cm = r omega to combine translational and rotational kinetic energy, distinguishes pure rolling (energy conserved) from slipping (kinetic friction dissipates energy).
- [Topic 6.6: Motion of Orbiting Satellites](/ap-physics-c-mechanics/unit-6/6-motion-of-orbiting-satellites/study-guide/nmLPsSq9JDXcENSW): Uses conservation of energy and angular momentum to analyze circular and elliptical orbits, deriving orbital speed, total mechanical energy E = -GMm/(2r), and escape velocity v_esc = sqrt(2GM/r).

## Hardest Topics And Analytics

Snapshot: practice snapshot
This snapshot uses Fiveable practice activity to show where students tend to miss questions and which review moves are worth prioritizing first.
- **61% average MCQ accuracy** (Across 2.0k multiple-choice practice attempts for this unit.)
- **2.0k MCQ attempts** (Practice activity included in this snapshot.)
- **49% average FRQ score** (Across 8 scored free-response attempts for this unit.)
- **Topic 6.6: Motion of Orbiting Satellites**: 43% MCQ miss rate across 246 attempts. Review Motion of Orbiting Satellites with attention to how the concept appears in AP-style source and evidence questions.
- **Topic 6.3: Angular Momentum and Angular Impulse**: 42% MCQ miss rate across 498 attempts. Review Angular Momentum and Angular Impulse with attention to how the concept appears in AP-style source and evidence questions.
- **Topic 6.4: Conservation of Angular Momentum**: 34% MCQ miss rate across 271 attempts. Review Conservation of Angular Momentum with attention to how the concept appears in AP-style source and evidence questions.
- **Topic 6.1: Rotational Kinetic Energy**: 33% MCQ miss rate across 379 attempts. Review Rotational Kinetic Energy with attention to how the concept appears in AP-style source and evidence questions.

## Review Notes

### Topic 6.1: Rotational Kinetic Energy

A rigid body spinning about any axis has rotational kinetic energy K_rot = 1/2 I omega^2. This is a scalar, so it adds directly to translational kinetic energy. When a rigid body both translates and rotates, K_tot = 1/2 m v_cm^2 + 1/2 I omega^2. A system can have rotational kinetic energy even when its center of mass is stationary, because individual mass elements still have linear speed.

- **K_rot = 1/2 I omega^2**: Rotational kinetic energy depends on the moment of inertia I about the rotation axis and the angular velocity omega. It is a scalar.
- **Total kinetic energy**: K_tot = K_trans + K_rot = 1/2 m v_cm^2 + 1/2 I omega^2 for any rigid body that both translates and rotates.
- **Stationary center of mass**: A spinning object whose center of mass is at rest still has rotational kinetic energy because its mass elements move in circles.
- **Moment of inertia I**: Quantifies how mass is distributed relative to the rotation axis; determines how much rotational kinetic energy a body stores at a given omega.

**Checkpoint:** A solid disk (I = 1/2 m r^2) and a hoop (I = m r^2) of equal mass and radius spin at the same omega. Which has more rotational kinetic energy, and by what factor?

Object | Moment of inertia I | K_rot at same omega
--- | --- | ---
Solid disk | 1/2 m r^2 | 1/4 m r^2 omega^2
Hoop (thin ring) | m r^2 | 1/2 m r^2 omega^2
Solid sphere | 2/5 m r^2 | 1/5 m r^2 omega^2
Thin rod (center) | 1/12 m L^2 | 1/24 m L^2 omega^2

### Topic 6.2: Torque and Work

A torque transfers energy into or out of a rotating system when it acts through an angular displacement. The work done is W = integral from theta_1 to theta_2 of tau d theta. For constant torque, W = tau * delta theta. On a torque-versus-angular-position graph, work equals the area under the curve. The rotational work-energy theorem states that the net work done by all torques equals the change in rotational kinetic energy.

- **W = integral tau d theta**: General expression for work done by a torque over an angular displacement; reduces to W = tau * delta theta when torque is constant.
- **Area under tau vs theta graph**: Graphical method to find rotational work without integration; positive area means energy added, negative area means energy removed.
- **Rotational work-energy theorem**: Net rotational work equals the change in rotational kinetic energy: W_net = delta K_rot.
- **Sign of rotational work**: Work is positive when torque and angular displacement are in the same direction, negative when they are opposite.

**Checkpoint:** A torque that varies as tau = 3 theta (in N*m, theta in radians) acts on a disk from theta = 0 to theta = 2 rad. What is the total work done on the disk?

Quantity | Linear analog | Rotational version
--- | --- | ---
Work | W = integral F dx | W = integral tau d theta
Constant-force/torque work | W = F * delta x | W = tau * delta theta
Work-energy theorem | W_net = delta K_trans | W_net = delta K_rot

### Topic 6.3: Angular Momentum and Angular Impulse

Angular momentum has two useful forms: L = I omega for a rigid body about a fixed axis, and L = r x p (vector cross product) for any object about a chosen point. The choice of reference point matters because it changes the value of L. Even an object moving in a straight line has nonzero angular momentum about any point not on its line of motion. Angular impulse equals the integral of tau dt and equals the change in angular momentum: delta L = integral tau dt. On a torque-versus-time graph, angular impulse is the area under the curve, and the slope of an L-versus-time graph equals the net torque.

- **L = I omega**: Angular momentum of a rigid body rotating about a fixed axis; units are kg*m^2/s.
- **L = r x p**: Vector angular momentum of any object about a reference point; magnitude is m v r sin(theta) where theta is the angle between r and v.
- **Angular impulse = integral tau dt**: The rotational analog of linear impulse; equals the change in angular momentum of the system.
- **tau_net = dL/dt**: Net external torque equals the time rate of change of angular momentum; for constant I this reduces to tau_net = I alpha.
- **Torque-time graph area**: The area under a tau-versus-t graph gives the angular impulse delivered to the system over that time interval.

**Checkpoint:** A point mass moves in a straight line at constant velocity. Explain why its angular momentum about a point off its path is nonzero and constant.

Concept | Linear version | Rotational version
--- | --- | ---
Momentum | p = m v | L = I omega or r x p
Impulse | J = integral F dt | Angular impulse = integral tau dt
Impulse-momentum theorem | J = delta p | Angular impulse = delta L
Newton's second law | F_net = dp/dt | tau_net = dL/dt

### Topic 6.4: Conservation of Angular Momentum

The total angular momentum of a system is the sum of the angular momenta of all its parts. If the net external torque on a system is zero, total angular momentum is conserved. If the net external torque is nonzero, angular momentum is transferred between the system and its environment by an amount equal to the angular impulse. A nonrigid system can change its angular speed without any external torque if it redistributes mass, changing I while L stays constant (the classic spinning-skater scenario). System selection is critical: choose a system boundary where all relevant torques are internal to apply conservation.

- **Conservation condition**: Total angular momentum is constant when the net external torque about the chosen axis is zero.
- **L_total = sum of L_i**: Angular momenta of all parts of a system add as vectors about the same axis.
- **Nonrigid system redistribution**: When a skater pulls arms inward, I decreases and omega increases so that L = I omega remains constant.
- **Newton's third law for torques**: Internal torque pairs are equal and opposite, so they cancel in the total angular momentum of the system.
- **System boundary selection**: Choosing the system to include all objects exerting torques on each other makes those torques internal and allows conservation to apply.

**Checkpoint:** A student sits on a frictionless rotating stool holding a spinning bicycle wheel with its axis vertical. The student flips the wheel upside down. Describe what happens to the student's rotation and explain why using angular momentum conservation.

Condition | Net external torque | Angular momentum
--- | --- | ---
Isolated system | Zero | Conserved
External torque applied | Nonzero | Changes by angular impulse
Nonrigid, no external torque | Zero | Conserved; omega changes as I changes

### Topic 6.5: Rolling Motion

When an object rolls without slipping, its center-of-mass translation and its rotation are linked by v_cm = r omega and a_cm = r alpha. Total kinetic energy is K_tot = 1/2 m v_cm^2 + 1/2 I omega^2. Because static friction does no work in pure rolling, mechanical energy is conserved and you can use energy methods directly. When an object slips, kinetic friction acts at the contact point, the no-slip constraint breaks down, and kinetic friction dissipates energy from the system.

- **No-slip condition**: v_cm = r omega and a_cm = r alpha; links translational and rotational motion so the contact point has zero velocity relative to the surface.
- **K_tot = K_trans + K_rot**: For a rolling object: K_tot = 1/2 m v_cm^2 + 1/2 I omega^2; substitute v_cm = r omega to express everything in terms of v_cm.
- **Static friction in pure rolling**: Provides the torque needed to maintain rolling but does no work because the contact point has zero velocity; mechanical energy is conserved.
- **Slipping condition**: v_cm is not equal to r omega; kinetic friction acts and dissipates energy, so mechanical energy is not conserved.
- **Rolling on an incline**: Use energy conservation: mgh = 1/2 m v_cm^2 + 1/2 I omega^2. Objects with larger I/mr^2 ratios reach the bottom more slowly.

**Checkpoint:** A solid sphere (I = 2/5 m r^2) and a hollow sphere (I = 2/3 m r^2) of equal mass and radius start from rest at the top of the same incline. Which reaches the bottom first, and why?

Object | I / (m r^2) | Fraction of K_tot that is rotational
--- | --- | ---
Hoop | 1 | 1/2
Hollow sphere | 2/3 | 2/5
Solid disk | 1/2 | 1/3
Solid sphere | 2/5 | 2/7

### Topic 6.6: Motion of Orbiting Satellites

For a satellite of negligible mass orbiting a massive central body M, gravity provides centripetal force and two conservation laws govern the motion. In circular orbits, total mechanical energy E = -GMm/(2r), kinetic energy K = GMm/(2r), and gravitational potential energy U = -GMm/r are all constant, as is angular momentum L = m v r. In elliptical orbits, total mechanical energy and angular momentum are still conserved, but K and U each vary as the satellite moves closer to or farther from the central body. Escape velocity from radius r is v_esc = sqrt(2GM/r), which corresponds to total mechanical energy equal to zero.

- **Circular orbital speed**: v_circ = sqrt(GM/r); derived by setting gravitational force equal to centripetal force.
- **Total mechanical energy (circular orbit)**: E = -GMm/(2r); negative value indicates a bound orbit. K = -E and U = 2E.
- **Gravitational potential energy**: U = -GMm/r; defined as zero at infinite separation, so U is always negative for bound systems.
- **Escape velocity**: v_esc = sqrt(2GM/r); the minimum speed needed for a satellite to escape to infinity with zero kinetic energy remaining.
- **Elliptical orbit conservation**: Total mechanical energy and angular momentum L = m v r sin(theta) are constant throughout an elliptical orbit; K and U individually vary.

**Checkpoint:** A satellite in a circular orbit of radius r is given a brief forward thrust that increases its speed. Describe qualitatively what happens to its orbit shape, total energy, and angular momentum immediately after the thrust.

Orbit type | Total energy E | Angular momentum L | K and U individually
--- | --- | --- | ---
Circular | Constant, -GMm/(2r) | Constant | Both constant
Elliptical | Constant (negative) | Constant | Each varies
Escape (parabolic) | Zero | Constant | Each varies

## Study Guides

- [6.1 Rotational Kinetic Energy](/ap-physics-c-mechanics/unit-6/1-rotational-kinetic-energy/study-guide/Y5pLDWQTbxH05tCF)
- [6.2 Torque and Work](/ap-physics-c-mechanics/unit-6/2-torque-and-work/study-guide/IDr6scmUlLJQ3Uub)
- [6.3 Angular Momentum and Angular Impulse](/ap-physics-c-mechanics/unit-6/3-angular-momentum-and-angular-impulse/study-guide/3jrKVVLAakxu58LX)
- [6.4 Conservation of Angular Momentum](/ap-physics-c-mechanics/unit-6/4-conservation-of-angular-momentum/study-guide/9JJXeFccr7Xo7FHS)
- [6.5 Kinetic Energy of a System with Translational and Rotational Motion](/ap-physics-c-mechanics/unit-6/5-kinetic-energy-of-a-system-with-translational-and-rotational-motion/study-guide/tpS8vdLgJ6AQpm2V)
- [6.6 Motion of Orbiting Satellites](/ap-physics-c-mechanics/unit-6/6-motion-of-orbiting-satellites/study-guide/nmLPsSq9JDXcENSW)

## Practice Preview

### Multiple-choice practice

- **AP-style practice question**: Practice 3: Scientific Questioning and Argumentation | Torque $$\tau$$ decreases linearly from $$\tau_{max}$$ at $$\theta=0$$ to zero at $$\theta=\Theta$$. Does the total work equal $$\tau_{max}\Theta$$?
- **AP-style practice question**: Practice 3: Scientific Questioning and Argumentation | A bowling ball is released with a forward linear velocity $$v$$ and a very large forward angular velocity $$\omega$$ such that $$R\omega > v$$. A student claims the friction force acts in the direction of motion. Which justification supports this?
- **AP-style practice question**: Practice 3: Scientific Questioning and Argumentation | A solid sphere slides with initial speed $$v_0$$ and zero rotation. By the time it begins rolling without slipping, its speed is $$5/7 v_0$$. A student claims that mechanical energy was not conserved. Which evidence supports this claim?
- **AP-style practice question**: Practice 3: Scientific Questioning and Argumentation | A wheel is released on a rough surface with initial velocity $$v_0$$ and zero rotation. A student plots the linear velocity $$v$$ and the tangential velocity $$R\omega$$ versus time. Which feature of the graph justifies that the wheel is slipping for the first few seconds?
- **AP-style practice question**: Practice 3: Scientific Questioning and Argumentation | A solid sphere of mass $$M$$ and radius $$R$$ is thrown horizontally along a rough floor with initial speed $$v_0$$ and zero initial angular velocity. A student claims the sphere's linear speed will decrease until it begins to roll without slipping. Which statement best supports this claim using physical principles?
- **AP-style practice question**: Practice 3: Scientific Questioning and Argumentation | A bicycle wheel of radius $$R$$ is spinning with angular velocity $$\omega_0$$ when it is gently dropped onto a rough horizontal surface with no initial linear velocity. A student observes the wheel accelerates forward. Which reasoning correctly justifies this observation?

### FRQ practice

- **Rotational inertia and angular momentum conservation**: FRQ 4 – Qualitative/Quantitative Translation | Rotational inertia and angular momentum conservation
- **Rotational kinetic energy and angular momentum of disk**: FRQ 2 – Translation Between Representations | Rotational kinetic energy and angular momentum of disk
- **Rotational inertia from falling mass acceleration**: FRQ 3 – Experimental Design | Rotational inertia from falling mass acceleration

## Key Terms

- **angular displacement**: The angle in radians through which a rigid body rotates about a specified axis, calculated as delta theta = theta minus theta_0. It appears in the rotational work integral W = integral tau d theta.
- **impulse-momentum theorem**: In rotational form: the angular impulse delivered to a system equals its change in angular momentum, delta L = integral tau dt. This is the rotational analog of J = delta p.
- **scalar**: A physical quantity described by magnitude only, without direction. Rotational kinetic energy and work are scalars, which is why K_rot adds directly to K_trans.
- **two-body gravitational system**: A system of a massive central object and an orbiting satellite interacting only via gravity. When the satellite mass is negligible, the central object is treated as stationary and conservation laws govern the satellite's orbit.

## Common Mistakes

- **Forgetting to include both K_trans and K_rot**: For a rolling object, total kinetic energy is K_tot = 1/2 m v_cm^2 + 1/2 I omega^2. Counting only translational kinetic energy underestimates the total and gives wrong speeds at the bottom of inclines.
- **Applying angular momentum conservation when external torques exist**: Conservation of angular momentum requires zero net external torque about the chosen axis. Friction from a surface or a pivot exerting a torque means angular momentum is not conserved for that system.
- **Confusing the two forms of angular momentum**: L = I omega applies to rigid bodies rotating about a fixed axis. L = r x p applies to any object about any reference point, including a point mass moving in a straight line. Using the wrong form leads to incorrect magnitudes and directions.
- **Treating gravitational potential energy as mgh in orbital problems**: For satellites, gravitational potential energy is U = -GMm/r, not mgh. Using mgh is only valid near Earth's surface. Orbital energy calculations require U = -GMm/r and E = -GMm/(2r).
- **Assuming static friction does work during rolling**: In pure rolling without slipping, the contact point has zero instantaneous velocity, so static friction does no work and mechanical energy is conserved. Only kinetic friction during slipping dissipates energy.

## Exam Connections

- **Multi-step energy and momentum accounting**: Free-response questions in this unit frequently require you to apply both energy conservation and angular momentum conservation in sequence within the same problem. A common structure is: find the angular speed after a collision or mass redistribution using angular momentum conservation, then use that result to find kinetic energy or height using energy conservation. Keeping track of which quantities are conserved at each stage is the central skill.
- **Graphical interpretation of rotational quantities**: Multiple-choice and free-response questions often present torque-versus-time or torque-versus-angle graphs and ask you to extract angular impulse or work as areas under the curve, or to identify net torque as the slope of an angular momentum graph. Practicing these graphical readings directly from the equations W = integral tau d theta and delta L = integral tau dt is essential.
- **Justifying conservation law applicability**: A recurring task is explaining in words why a conservation law does or does not apply to a given system. For angular momentum, you must identify whether net external torque is zero and justify your system boundary choice. For energy in rolling problems, you must state whether the no-slip condition holds and whether friction does work. Clear, equation-linked justifications are expected in free-response scoring.

## Final Review Checklist

- **Unit 6 final review checklist**: Use this list to confirm you can handle every major skill before your exam.
- **Calculate rotational and total kinetic energy**: Apply K_rot = 1/2 I omega^2 and K_tot = K_trans + K_rot for rigid bodies with known moments of inertia such as disks, hoops, and spheres.
- **Find work done by a torque**: Evaluate W = integral tau d theta analytically for variable torques and graphically as area under a tau-versus-theta curve; apply the rotational work-energy theorem.
- **Compute angular momentum in both forms**: Use L = I omega for rigid bodies about a fixed axis and L = r x p (magnitude m v r sin theta) for point masses about any reference point.
- **Apply conservation of angular momentum**: Identify whether net external torque is zero, select the correct system boundary, and solve for unknown angular speeds when moment of inertia changes.
- **Solve rolling problems with energy methods**: Use v_cm = r omega to link translation and rotation, write K_tot = 1/2 m v_cm^2 + 1/2 I omega^2, and apply energy conservation for rolling without slipping on inclines.
- **Analyze satellite orbits with conservation laws**: Derive circular orbital speed and total energy, use E = -GMm/(2r) and v_esc = sqrt(2GM/r), and explain which quantities are conserved in elliptical versus circular orbits.

## Study Plan

- **Step 1: Rotational kinetic energy and torque work (Topics 6.1-6.2)**: Read the Topic 6.1 and 6.2 guides on Fiveable. Practice writing K_rot = 1/2 I omega^2 for disks, hoops, and spheres, then evaluate W = integral tau d theta for both constant and variable torques. Confirm you can read area off a tau-versus-theta graph.
- **Step 2: Angular momentum and angular impulse (Topic 6.3)**: Work through the Topic 6.3 guide. Practice computing L = I omega for rigid bodies and L = r x p for point masses at various reference points. Sketch torque-versus-time graphs and identify angular impulse as the area under the curve.
- **Step 3: Conservation of angular momentum (Topic 6.4)**: Use the Topic 6.4 guide to practice identifying zero-external-torque conditions and selecting system boundaries. Solve problems where a skater, diver, or rotating platform changes shape, and verify that L = I omega is conserved while omega changes.
- **Step 4: Rolling motion (Topic 6.5)**: Work through the Topic 6.5 guide. Set up K_tot = 1/2 m v_cm^2 + 1/2 I omega^2 with the no-slip substitution v_cm = r omega for incline problems. Compare final speeds for objects with different I values and explain why the hoop is slowest.
- **Step 5: Satellite orbits and full-unit FRQ practice (Topic 6.6)**: Read the Topic 6.6 guide and derive E = -GMm/(2r) and v_esc = sqrt(2GM/r) from scratch. Then use the available FRQ practice on Fiveable to work multi-part problems that combine rolling, angular momentum conservation, or orbital energy in a single question.

## More Ways To Review

- [Topic study guides](/ap-physics-c-mechanics/unit-6#topics)
- [FRQ practice](/ap-physics-c-mechanics/frq-practice)
- [Cram archive videos](/cram-archives?subject=ap-physics-c-mechanics&unit=unit-6)
- [Key terms](/ap-physics-c-mechanics/key-terms)

## FAQs

### What topics are covered in AP Physics Mech Unit 6?

AP Physics C: Mechanics Unit 6 covers 6 topics: Rotational Kinetic Energy, Torque and Work, Angular Momentum and Angular Impulse, Conservation of Angular Momentum, Rolling, and Motion of Orbiting Satellites. Together they apply energy and momentum concepts to rotating systems, including objects rolling without slipping and orbiting satellites. See the full topic list at [/ap-physics-c-mechanics/unit-6](/ap-physics-c-mechanics/unit-6).

### How much of the AP Physics Mech exam is Unit 6?

Unit 6 makes up 10-15% of the AP Physics C: Mechanics exam. That weight comes from topics like Rotational Kinetic Energy, Conservation of Angular Momentum, Rolling, and Motion of Orbiting Satellites. It's a meaningful chunk of the test, so understanding when angular momentum is conserved versus when it changes is especially important.

### What's on the AP Physics Mech Unit 6 progress check (MCQ and FRQ)?

The AP Physics C: Mechanics Unit 6 progress check includes both MCQ and FRQ parts drawn from all six unit topics: Rotational Kinetic Energy, Torque and Work, Angular Momentum and Angular Impulse, Conservation of Angular Momentum, Rolling, and Motion of Orbiting Satellites. MCQ questions test conceptual understanding and calculation, while the FRQ section asks you to set up and solve multi-part problems involving angular momentum or rolling motion. For matched practice aligned to the progress check, visit [/ap-physics-c-mechanics/unit-6](/ap-physics-c-mechanics/unit-6).

### How do I practice AP Physics Mech Unit 6 FRQs?

To practice Unit 6 FRQs, focus on the topics that appear most often in free-response questions: Conservation of Angular Momentum, Rolling without slipping, and Torque and Work. Typical FRQ formats ask you to derive an expression for angular momentum before and after a collision, calculate rotational kinetic energy, or analyze a rolling object on an incline. Work through each part by writing out your setup, applying the correct conservation law, and checking units. Find Unit 6 FRQ practice at [/ap-physics-c-mechanics/unit-6](/ap-physics-c-mechanics/unit-6).

### Where can I find AP Physics Mech Unit 6 practice questions?

You can find AP Physics C: Mechanics Unit 6 practice questions, including multiple-choice and practice test problems, at [/ap-physics-c-mechanics/unit-6](/ap-physics-c-mechanics/unit-6). That page has MCQ sets and FRQs covering all six topics: Rotational Kinetic Energy, Torque and Work, Angular Momentum, Conservation of Angular Momentum, Rolling, and Motion of Orbiting Satellites.

### How should I study AP Physics Mech Unit 6?

Start Unit 6 by building a solid feel for rotational kinetic energy and how it connects to the linear kinetic energy formulas you already know. Then work through Torque and Work, Angular Momentum and Angular Impulse, and Conservation of Angular Momentum in order, since each concept builds on the last. Rolling without slipping trips up a lot of students, so practice breaking it into translational and rotational parts separately before combining them. Finish with Motion of Orbiting Satellites, which ties angular momentum to gravity. For topic guides and practice sets, go to [/ap-physics-c-mechanics/unit-6](/ap-physics-c-mechanics/unit-6).

## Structured Data

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{"@context":"https://schema.org","@type":"FAQPage","inLanguage":"en","mainEntity":[{"@type":"Question","@id":"https://fiveable.me/ap-physics-c-mechanics/unit-6#what-topics-are-covered-in-ap-physics-mech-unit-6","name":"What topics are covered in AP Physics Mech Unit 6?","acceptedAnswer":{"@type":"Answer","text":"AP Physics C: Mechanics Unit 6 covers 6 topics: Rotational Kinetic Energy, Torque and Work, Angular Momentum and Angular Impulse, Conservation of Angular Momentum, Rolling, and Motion of Orbiting Satellites. Together they apply energy and momentum concepts to rotating systems, including objects rolling without slipping and orbiting satellites. See the full topic list at <a href=\"/ap-physics-c-mechanics/unit-6\">/ap-physics-c-mechanics/unit-6</a>."}},{"@type":"Question","@id":"https://fiveable.me/ap-physics-c-mechanics/unit-6#how-much-of-the-ap-physics-mech-exam-is-unit-6","name":"How much of the AP Physics Mech exam is Unit 6?","acceptedAnswer":{"@type":"Answer","text":"Unit 6 makes up 10-15% of the AP Physics C: Mechanics exam. That weight comes from topics like Rotational Kinetic Energy, Conservation of Angular Momentum, Rolling, and Motion of Orbiting Satellites. It's a meaningful chunk of the test, so understanding when angular momentum is conserved versus when it changes is especially important."}},{"@type":"Question","@id":"https://fiveable.me/ap-physics-c-mechanics/unit-6#whats-on-the-ap-physics-mech-unit-6-progress-check-mcq-and-frq","name":"What's on the AP Physics Mech Unit 6 progress check (MCQ and FRQ)?","acceptedAnswer":{"@type":"Answer","text":"The AP Physics C: Mechanics Unit 6 progress check includes both MCQ and FRQ parts drawn from all six unit topics: Rotational Kinetic Energy, Torque and Work, Angular Momentum and Angular Impulse, Conservation of Angular Momentum, Rolling, and Motion of Orbiting Satellites. MCQ questions test conceptual understanding and calculation, while the FRQ section asks you to set up and solve multi-part problems involving angular momentum or rolling motion. For matched practice aligned to the progress check, visit <a href=\"/ap-physics-c-mechanics/unit-6\">/ap-physics-c-mechanics/unit-6</a>."}},{"@type":"Question","@id":"https://fiveable.me/ap-physics-c-mechanics/unit-6#how-do-i-practice-ap-physics-mech-unit-6-frqs","name":"How do I practice AP Physics Mech Unit 6 FRQs?","acceptedAnswer":{"@type":"Answer","text":"To practice Unit 6 FRQs, focus on the topics that appear most often in free-response questions: Conservation of Angular Momentum, Rolling without slipping, and Torque and Work. Typical FRQ formats ask you to derive an expression for angular momentum before and after a collision, calculate rotational kinetic energy, or analyze a rolling object on an incline. Work through each part by writing out your setup, applying the correct conservation law, and checking units. Find Unit 6 FRQ practice at <a href=\"/ap-physics-c-mechanics/unit-6\">/ap-physics-c-mechanics/unit-6</a>."}},{"@type":"Question","@id":"https://fiveable.me/ap-physics-c-mechanics/unit-6#where-can-i-find-ap-physics-mech-unit-6-practice-questions","name":"Where can I find AP Physics Mech Unit 6 practice questions?","acceptedAnswer":{"@type":"Answer","text":"You can find AP Physics C: Mechanics Unit 6 practice questions, including multiple-choice and practice test problems, at <a href=\"/ap-physics-c-mechanics/unit-6\">/ap-physics-c-mechanics/unit-6</a>. That page has MCQ sets and FRQs covering all six topics: Rotational Kinetic Energy, Torque and Work, Angular Momentum, Conservation of Angular Momentum, Rolling, and Motion of Orbiting Satellites."}},{"@type":"Question","@id":"https://fiveable.me/ap-physics-c-mechanics/unit-6#how-should-i-study-ap-physics-mech-unit-6","name":"How should I study AP Physics Mech Unit 6?","acceptedAnswer":{"@type":"Answer","text":"Start Unit 6 by building a solid feel for rotational kinetic energy and how it connects to the linear kinetic energy formulas you already know. Then work through Torque and Work, Angular Momentum and Angular Impulse, and Conservation of Angular Momentum in order, since each concept builds on the last. Rolling without slipping trips up a lot of students, so practice breaking it into translational and rotational parts separately before combining them. Finish with Motion of Orbiting Satellites, which ties angular momentum to gravity. For topic guides and practice sets, go to <a href=\"/ap-physics-c-mechanics/unit-6\">/ap-physics-c-mechanics/unit-6</a>."}}]}
```