AP Physics Unit Weightings: 28 Units, 4 Courses

The four AP Physics courses hold 28 units between them: 8 in Physics 1, 7 in Physics 2, 7 in C: Mechanics and 6 in C: Electricity and Magnetism. Every published weighting is a range, not a fixed figure, and it describes the multiple-choice section only rather than the whole exam.

Spans all 28 units of all four courses. Weightings and class-period estimates are transcribed from the Course at a Glance spreads and the Exam Information sections of the four course and exam descriptions, effective Fall 2024, version 1: AP Physics 1 printed pages 13 to 15 and 171, AP Physics 2 printed pages 13 to 15 and 183, AP Physics C: Mechanics printed pages 13 to 15 and 165, AP Physics C: Electricity and Magnetism printed pages 13 to 15 and 139. Every weighting is stated twice in its own CED and the two statements agree in all 28 cases.

What the weighting number actually measures

The heading above every one of these tables in the course and exam descriptions reads "Exam Weighting for the Multiple-Choice Section of the AP Exam". That qualifier does most of the work on this page, and it is dropped almost everywhere the numbers get reprinted.

All four exams split 50 percent multiple choice and 50 percent free response. Unit weightings govern the multiple-choice half. The free-response half is not divided by unit at all; the CED divides it by science practice and by question type instead, which is what the page on the AP Physics science practices sets out.

So a unit at 20 to 25 percent is at 20 to 25 percent of half the exam, which is 10 to 12.5 percent of the score. Treating a unit weighting as a share of the whole exam roughly doubles it.

Every number below comes from the current course and exam descriptions, all four effective Fall 2024, version 1. Each course states the weightings twice, once on the Course at a Glance spread and once in the Exam Information section, and the two agree in all 28 cases.

AP Physics 1: eight units

Unit	Title	Exam weighting	Class periods
---	---	:-:	:-:
1	Kinematics	10-15%	about 12 to 17
2	Force and Translational Dynamics	18-23%	about 22 to 27
3	Work, Energy, and Power	18-23%	about 22 to 27
4	Linear Momentum	10-15%	about 10 to 15
5	Torque and Rotational Dynamics	10-15%	about 15 to 20
6	Energy and Momentum of Rotating Systems	5-8%	about 8 to 14
7	Oscillations	5-8%	about 5 to 10
8	Fluids	10-15%	about 12 to 17

The lower bounds sum to 86 percent and the upper bounds to 122 percent. Class periods sum to about 106 to 147.

Units 2 and 3 carry the same 18 to 23 percent band and the same 22 to 27 period estimate, so the CED gives dynamics and energy equal billing in this course. Units 6 and 7 share the 5 to 8 percent band, and those two are the lightest units anywhere in the AP Physics program: no other unit in any of the four courses has a lower bound below 10 percent.

AP Physics 2: seven units

AP Physics 2 numbers its units 9 through 15, continuing the AP Physics 1 sequence rather than restarting.

Unit	Title	Exam weighting	Class periods
---	---	:-:	:-:
9	Thermodynamics	15-18%	about 10 to 16
10	Electric Force, Field, and Potential	15-18%	about 14 to 21
11	Electric Circuits	15-18%	about 12 to 20
12	Magnetism and Electromagnetism	12-15%	about 10 to 13
13	Geometric Optics	12-15%	about 8 to 12
14	Waves, Sound, and Physical Optics	12-15%	about 14 to 23
15	Modern Physics	12-15%	about 14 to 22

Lower bounds sum to 93 percent, upper bounds to 114 percent. Class periods sum to about 82 to 127.

This is the flattest course of the four. Only two distinct bands appear across all seven units, 15 to 18 percent for the first three and 12 to 15 percent for the last four, and every band is three percentage points wide. Nothing in AP Physics 2 can be safely skipped on weighting grounds, because the gap between its heaviest and lightest unit is three points at either bound.

The pacing tells a different story from the weighting. Unit 13 carries the same 12 to 15 percent as Unit 14, but the CED allows Unit 14 roughly twice the class time.

AP Physics C: Mechanics: seven units

The unit numbers and titles repeat AP Physics 1's first seven exactly. The weightings do not.

Unit	Title	Exam weighting	Class periods
---	---	:-:	:-:
1	Kinematics	10-15%	about 14 to 19
2	Force and Translational Dynamics	20-25%	about 15 to 25
3	Work, Energy, and Power	15-25%	about 12 to 17
4	Linear Momentum	10-20%	about 11 to 15
5	Torque and Rotational Dynamics	10-15%	about 14 to 20
6	Energy and Momentum of Rotating Systems	10-15%	about 13 to 19
7	Oscillations	10-15%	about 12 to 17

Lower bounds sum to 85 percent, upper bounds to 130 percent. Class periods sum to about 91 to 132.

Unit 2 is the only unit in the entire AP Physics program with a lower bound of 20 percent. Checked against all 28 units, the next highest floors are the 18 percent of AP Physics 1 Units 2 and 3. If you are deciding where a calculus-based mechanics course cannot afford to be thin, this is the number that says so.

The contrast with AP Physics 1 is worth pulling out, because the two courses share these unit titles and a great deal of web content treats them as interchangeable. AP Physics 1 Unit 7, Oscillations, is a 5 to 8 percent unit. C: Mechanics Unit 7, same title, is a 10 to 15 percent unit with an extra topic on simple and physical pendulums.

AP Physics C: Electricity and Magnetism: six units

Six units, numbered 8 through 13, and the smallest unit count of the four courses.

Unit	Title	Exam weighting	Class periods
---	---	:-:	:-:
8	Electric Charges, Fields, and Gauss's Law	15-25%	about 12 to 24
9	Electric Potential	10-20%	about 10 to 20
10	Conductors and Capacitors	10-15%	about 8 to 16
11	Electric Circuits	15-25%	about 12 to 24
12	Magnetic Fields and Electromagnetism	10-20%	about 10 to 20
13	Electromagnetic Induction	10-20%	about 10 to 20

Lower bounds sum to 70 percent, upper bounds to 125 percent. Class periods sum to about 62 to 124.

This course is published with the loosest bands in the program. Five of its six units span ten percentage points, and only Unit 10 is pinned to five. Take the midpoint of every band and the six add up to 97.5, which is the only course of the four whose midpoints fall short of 100. The other three come in at 104, 103.5 and 107.5. Read that as a caution against midpoints rather than as a claim about the exam.

One pattern is exact and easy to miss: every class-period range here is precisely two to one, 12 to 24, 10 to 20, 8 to 16, and so on. The CED note beside the table says pacing covers both 45-minute periods for a full year and 90-minute periods for a single semester, and a two-to-one range is what that note produces. C: Mechanics prints a near-identical note and does not follow the pattern, so the interpretation holds for this course only.

All 28 units at once: what the full set looks like

Counting item by item across the whole program rather than course by course changes several impressions.

Only eight distinct weighting bands are used for 28 units:

Band	Units carrying it	Where
---	:-:	---
5-8%	2	AP Physics 1 Units 6 and 7
10-15%	9	AP Physics 1 Units 1, 4, 5, 8; C: Mechanics Units 1, 5, 6, 7; C: E&M Unit 10
10-20%	4	C: Mechanics Unit 4; C: E&M Units 9, 12, 13
12-15%	4	AP Physics 2 Units 12, 13, 14, 15
15-18%	3	AP Physics 2 Units 9, 10, 11
15-25%	3	C: Mechanics Unit 3; C: E&M Units 8 and 11
18-23%	2	AP Physics 1 Units 2 and 3
20-25%	1	C: Mechanics Unit 2

The counts add to 28.

On the width of the bands, which is the thing most often described with a superlative it has not earned: three widths exist. Nine units have a three-point band, and all nine sit in AP Physics 2 apart from AP Physics 1 Units 6 and 7. Twelve units have a five-point band. Seven units have a ten-point band, and those seven are C: Mechanics Units 3 and 4 plus C: E&M Units 8, 9, 11, 12 and 13. Ten points is the widest band published anywhere in the program, and it is a seven-way tie, so no unit page anywhere should describe its own range as the widest in its course without naming the units it ties with. Within C: E&M the tie is five units deep by itself. 9 plus 12 plus 7 is 28.

Four units reach a ceiling of 25 percent, the highest published anywhere: C: Mechanics Units 2 and 3, and C: E&M Units 8 and 11. One unit alone has a floor of 20 percent, C: Mechanics Unit 2. Two units alone dip to a floor of 5 percent, AP Physics 1 Units 6 and 7, and those same two are the only ones with a ceiling as low as 8 percent.

Why the ranges do not add to 100

They are not meant to. Each band is a statement about where one unit's share is expected to land, and the bands are published independently, so their bounds do not have to reconcile.

Course	Sum of lower bounds	Sum of upper bounds	Sum of midpoints
---	:-:	:-:	:-:
AP Physics 1	86%	122%	104
AP Physics 2	93%	114%	103.5
AP Physics C: Mechanics	85%	130%	107.5
AP Physics C: E&M	70%	125%	97.5

Every one of those ranges brackets 100, which is the only consistency check the published numbers can pass. For any course you can pick a value inside each band and have the eight, seven, seven or six values total exactly 100. What you cannot do is take all the lower bounds, or all the upper bounds, or all the midpoints, and expect a real exam.

The practical reading for planning: a unit's floor is what to assume when you are deciding what cannot be cut, and a unit's ceiling is what to assume when you are deciding how much practice a topic deserves.

Class periods, and the two pacing models

The period estimates come from the Course at a Glance spread rather than from the Exam Information section, and the assumption behind them is not the same in all four courses.

AP Physics 1 and AP Physics 2 both print: "pacing is based on 45-minute class periods, meeting five days each week for a full academic year." One model, one range per unit.

AP Physics C: Mechanics prints: "suggested pacing options are provided for both 45-minute periods meeting daily for a full year and for 90-minute periods meeting daily for a single semester."

AP Physics C: Electricity and Magnetism prints: "pacing is based on 45-minute class periods, meeting five days each week for a full academic year and for 90-minute periods meeting daily for a single semester."

Both Physics C courses therefore describe two schedules while showing one range per unit. In C: E&M every range is an exact two-to-one span, which is what a single figure covering both schedules would look like. In C: Mechanics the ranges are 14 to 19, 15 to 25, 12 to 17, 11 to 15, 14 to 20, 13 to 19 and 12 to 17, none of them two to one. The two courses describe their pacing the same way and present it differently, and a curriculum map should not assume the C: Mechanics numbers can be halved for a block schedule.

Program totals, added unit by unit: about 106 to 147 periods for AP Physics 1, 82 to 127 for AP Physics 2, 91 to 132 for C: Mechanics, and 62 to 124 for C: E&M. These leave no room for the Progress Checks, review, or the labs the courses require, so treat them as content time rather than calendar time.

Exam format, and it is the same for all four

The four Exam Overview pages print the same structure, word for word in most places.

Feature	All four AP Physics exams
Total length	3 hours
Section I	42 multiple-choice questions, 50%, 85 minutes
Section II	4 free-response questions, 50%, 95 minutes
Calculator	Four-function, scientific, or graphing, allowed on both sections

The four free-response questions are the same four types in every course:

Question	Type	Points	Suggested time
:-:	---	:-:	:-:
1	Mathematical Routines (MR)	10	20 to 25 minutes
2	Translation Between Representations (TBR)	12	25 to 30 minutes
3	Experimental Design and Analysis (LAB)	10	25 to 30 minutes
4	Qualitative/Quantitative Translation (QQT)	8	15 to 20 minutes

Forty points across the section. Two details are easy to miss. First, the suggested times run from 85 minutes at the low end to 105 at the high end against a 95-minute section, so the generous end of every suggestion cannot all be taken. Second, the LAB question is worth 10 points on a 25 to 30 minute suggestion while the TBR question is worth 12 on the same suggestion, making LAB the lowest-scoring minute in the section.

One wording difference between the courses: AP Physics 1, C: Mechanics and C: E&M each say the four question types are "listed below in the order they will appear on the exam". The AP Physics 2 CED instead says they are "listed below" and that "Each question type appears on the exam", without the order clause, although its Exam Overview table still numbers them 1 through 4 in the same sequence.

Using these numbers on a syllabus or curriculum map

Three things this table supports, and one it does not.

Allocating instructional time. Use the class-period range, not the weighting. They are not proportional to each other, and the CED never claims they are. AP Physics 2 Unit 13 and Unit 14 share a weighting band and differ by roughly a factor of two in periods.

Deciding assessment coverage. Use the weighting range, halved, if you want a share of the whole exam. A unit at 12 to 15 percent is 6 to 7.5 percent of the score.

Comparing the two mechanics courses. Put AP Physics 1 Units 1 to 7 next to C: Mechanics Units 1 to 7 and the differences are structural rather than cosmetic: identical titles, different bands in five of the seven, and an eighth unit on fluids that exists only in AP Physics 1.

What these numbers cannot tell you is how many questions on a given exam came from a given unit. The College Board publishes a target band, not a result, and the free-response half is not built from units at all.

Turning a unit weighting into a question count

AP Physics 1 Unit 2, Force and Translational Dynamics, is weighted 18 to 23 percent. How many of the 42 multiple-choice questions is that, and what share of the whole exam score does the unit represent?

The band applies to Section I only, which holds 42 questions.
Lower bound: $0.18 \times 42 = 7.56$ questions.
Upper bound: $0.23 \times 42 = 9.66$ questions.
A question count is a whole number, so the band admits 8 or 9 questions from this unit.
For the share of the whole exam, halve the band, because Section I is 50 percent of the score: $18/2 = 9$ and $23/2 = 11.5$ .
So Unit 2 is 9 to 11.5 percent of the total score, not 18 to 23 percent.

8 or 9 of the 42 multiple-choice questions, which is 9 to 11.5 percent of the exam score.

Checking the free-response time budget against the points

Section II is 95 minutes and 40 points across four questions worth 10, 12, 10 and 8. Compare a strictly proportional time budget with the CED's own suggested times.

Points total: $10 + 12 + 10 + 8 = 40$ .
Minutes per point if time follows points: $95 / 40 = 2.375$ minutes.
Mathematical Routines, 10 points: $10 \times 2.375 = 23.75$ minutes. CED suggests 20 to 25, so the proportional figure sits inside it.
Translation Between Representations, 12 points: $12 \times 2.375 = 28.5$ minutes. CED suggests 25 to 30, inside it again.
Experimental Design and Analysis, 10 points: $10 \times 2.375 = 23.75$ minutes. CED suggests 25 to 30, so the suggestion runs above the proportional share.
Qualitative/Quantitative Translation, 8 points: $8 \times 2.375 = 19$ minutes. CED suggests 15 to 20, inside it.
Adding the CED's own suggestions gives 85 minutes at the low end and 105 at the high end, against 95 available.

Three of the four suggested windows contain the proportional figure. The LAB question is the exception: the CED asks for 25 to 30 minutes on 10 points, the same window it gives the 12-point TBR question, so LAB is the least point-dense question in the section.

Frequently asked questions

What are the AP Physics 1 unit weightings?

Unit 1 Kinematics 10 to 15 percent, Unit 2 Force and Translational Dynamics 18 to 23 percent, Unit 3 Work, Energy, and Power 18 to 23 percent, Unit 4 Linear Momentum 10 to 15 percent, Unit 5 Torque and Rotational Dynamics 10 to 15 percent, Unit 6 Energy and Momentum of Rotating Systems 5 to 8 percent, Unit 7 Oscillations 5 to 8 percent, Unit 8 Fluids 10 to 15 percent. Those are shares of the 42-question multiple-choice section, which is half the exam score, not shares of the whole exam.

Why do the AP Physics unit weightings not add up to 100 percent?

Because each unit is published as a range and the ranges are set independently. Adding all the lower bounds gives 86 percent for AP Physics 1, 93 for AP Physics 2, 85 for C: Mechanics and 70 for C: Electricity and Magnetism. Adding all the upper bounds gives 122, 114, 130 and 125. Every one of those spans contains 100, so a real exam can pick one value inside each band and total 100. The bands themselves are targets, not a partition.

Which AP Physics unit is worth the most on the exam?

By the highest ceiling, four units tie at 25 percent: C: Mechanics Units 2 and 3, and C: Electricity and Magnetism Units 8 and 11. By the highest floor, one unit stands alone, C: Mechanics Unit 2 at 20 to 25 percent, which is the only unit in any of the four courses guaranteed at least a fifth of its multiple-choice section. Within AP Physics 1, Units 2 and 3 tie at 18 to 23 percent.

How many units are in each AP Physics course?

AP Physics 1 has 8, numbered 1 through 8. AP Physics 2 has 7, numbered 9 through 15, continuing the AP Physics 1 numbering rather than restarting. AP Physics C: Mechanics has 7, numbered 1 through 7 with the same titles as the first seven AP Physics 1 units. AP Physics C: Electricity and Magnetism has 6, numbered 8 through 13. That is 28 units across the program.

Is the AP Physics exam format the same for all four courses?

Yes, in the current course and exam descriptions. Each exam is 3 hours: Section I is 42 multiple-choice questions for 50 percent in 85 minutes, and Section II is 4 free-response questions for 50 percent in 95 minutes. A four-function, scientific, or graphing calculator is allowed on both sections of all four exams. The four free-response types are Mathematical Routines, Translation Between Representations, Experimental Design and Analysis, and Qualitative/Quantitative Translation, worth 10, 12, 10 and 8 points.

Do the class-period estimates mean I can plan a school year from them?

Only partly. They cover content time and nothing else. Summed unit by unit they come to about 106 to 147 periods for AP Physics 1, 82 to 127 for AP Physics 2, 91 to 132 for C: Mechanics and 62 to 124 for C: Electricity and Magnetism, with no allowance for the Progress Checks, laboratory work, review, or assessment. AP Physics 1 and 2 base their figures on 45-minute periods across a full year; both Physics C courses describe a 90-minute single-semester option as well.

Are AP Physics 1 and AP Physics C: Mechanics weighted the same?

No, and the shared unit titles hide it. Both courses have a Unit 2 called Force and Translational Dynamics, but AP Physics 1 weights it 18 to 23 percent and C: Mechanics weights it 20 to 25 percent. Unit 3 is 18 to 23 percent in AP Physics 1 and 15 to 25 percent in C: Mechanics. Unit 7, Oscillations, is 5 to 8 percent in AP Physics 1 and 10 to 15 percent in C: Mechanics. Only Units 1 and 5 carry the same band in both, and AP Physics 1 has an eighth unit on fluids that C: Mechanics does not.