AP Physics 1 forces and energy: a complete free course
Everything you need for the forces and energy part of AP Physics 1, in the order your class teaches it. Each lesson has clear notes, labelled diagrams and worked examples for every subtopic, then practice problems with hints and step-by-step solutions, AP-style free-response questions with scoring guides, and answers to the questions students ask most.
The 7 lessons
Lessons 1 to 6 cover Unit 2, Force and Translational Dynamics. Lesson 7 covers the first half of Unit 3, Work, Energy, and Power. Your progress on each lesson's problems shows here once you start.
- Lesson 1Newton's laws and forces
Free-body diagrams, Newton's three laws, net force, kinetic friction, elevators and apparent weight, Hooke's law and the force-probe lab.
- Forces and free-body diagrams
- Newton's three laws
- Net force (horizontal)
- Introduction to friction
- Vertical forces and elevators
- Spring forces and Hooke's law
- Lab: motion detectors and force probes
- Lesson 2Forces in systems and friction
Systems and internal forces, Atwood machines, static vs kinetic friction and the friction graph, blocks pulled over pulleys, inertial vs gravitational mass.
- Forces in systems
- Atwood machines
- Static vs kinetic friction
- Sliding blocks with a pulley
- Inertial vs gravitational mass
- Lesson 3Forces at angles and equilibrium
Resolving forces into components, angled pulls on frictionless and rough surfaces, pushing vs pulling, signs and lamps hung from cables in equilibrium.
- Resolving forces into components
- Forces at angles (no friction)
- Static equilibrium
- Forces at angles with friction
- Lesson 4Inclines, interacting blocks and centre of mass
Tilted axes on slopes, friction on inclines, the minimum μs to prevent slipping, measuring μ, blocks in contact and stacked, centre of mass.
- Forces on inclined planes
- Friction on slopes and minimal μs
- Interacting blocks
- Centre of mass
- Lesson 5Uniform circular motion
Centripetal acceleration and the net inward force, the stopper-on-a-string derivation and lab, a coin on a turntable, conical pendulums.
- Introduction to uniform circular motion
- Derivation: stopper on a string
- Coin on a disk
- Conical pendulums
- Lesson 6Curves, vertical circles and gravitation
Flat and banked curves, vertical loops and hills, Newton's law of gravitation, gravitational fields, satellite orbits and Kepler's laws.
- Banked vs unbanked curves
- Vertical circles and loops
- Universal gravitation and fields
- Orbits and Kepler's laws
- Lesson 7Work and conservation of energy
Work and the work-energy theorem, conservative forces, roller coasters and slides, elastic potential energy, friction and thermal energy, energy bar charts and graphs.
- Work and the work-energy theorem
- Conservative forces and conservation of energy
- Elastic potential energy
- Thermal energy and friction
- Energy bar charts
- Graphing energy: free fall vs springs
- Atwood machine with energy
How to use this course
- Before class: read the notes for the topic your teacher is about to start. Ten minutes of reading makes the lesson much easier to follow.
- After class: work through the worked examples with the solution covered, then try the practice problems. Use the hint before the solution.
- Before a test or quiz: do the free-response questions on paper under time, mark them with the scoring guide, and read the common mistakes list.
- Stuck? Each lesson's FAQ answers the questions students ask us most. If you are still stuck, a tutor can help.
How this links to the AP exam
Forces and energy are the core of AP Physics 1. On the exam, Unit 2 is weighted at about 18 to 23% and Unit 3 at about 18 to 23% of the multiple-choice score, and almost every free-response question uses Newton's second law or conservation of energy somewhere. The exam's four free-response question types are Mathematical Routines (MR), Translation Between Representations (TBR), Experimental Design and Analysis (LAB) and Qualitative/Quantitative Translation (QQT). The free-response questions in each lesson are labelled with the type they practise.
The lessons use only the equations on the AP Physics 1 equation sheet, with algebra and trigonometry. For the rest of the course, see all AP Physics 1 units, practice by unit and how AP Physics 1 free-response questions are marked.
Frequently asked questions
Is this course at the right level for the AP Physics 1 exam?
Yes. It follows the College Board's course framework for Unit 2 (Force and Translational Dynamics) and Unit 3 (Work, Energy, and Power). The problems use only the equations on the AP Physics 1 equation sheet and algebra and trigonometry, with no calculus, which is the level of the exam.
What order should I study the lessons in?
In order, 1 to 7. This is the order most AP Physics 1 classes teach forces and energy in the fall: Newton's laws, systems, angles and equilibrium, inclines and contact forces, circular motion, gravitation, then work and energy. Each lesson builds on the one before.
How long does each lesson take?
Reading the notes and examples takes 45 to 60 minutes. The practice problems and free-response questions take another 60 to 90 minutes. Most students do one lesson across a week of class, alongside their homework.
Do I need to sign up?
No. Everything is free and open. Your practice progress is saved in your own browser, so you can come back to it on the same device.
What comes before and after these lessons?
Before: Unit 1, kinematics (see our kinematics guide and kinematics practice). After: momentum, rotation, oscillations and fluids, which are covered in our AP Physics 1 units guide and practice by unit.
Can I get help with a lesson?
Yes. Our tutors teach AP Physics 1 live, 1-on-1 online, and can go through any lesson or your class assessments with you. Book a free demo class from the button on this page.