AP Physics 1 ›  Unit 2

Unit 2Ā Forces & Translational Dynamics

Why things move the way they do. Nine topics, one idea at the center of all of them: force causes acceleration.

šŸ“‹ 18–23% AP Exam WeightingšŸ• 17–23 Class PeriodsšŸ“ŗ 9 Episodesāœ… Progress Check 2
EP.2.1

Systems and Center of Mass

Before forces make sense, you need to know what point you're actually tracking when something moves.

SystemsCenter of mass
šŸ• 1–2 daysOpen →
EP.2.2

Forces and Free-Body Diagrams

Every physics problem starts here. Learn to draw every force acting on an object — nothing more, nothing less.

Contact forcesField forcesFree-body diagrams
šŸ• 2–3 daysOpen →
EP.2.3

Newton's Third Law

Every push has an equal push back. The most misunderstood law in physics, finally made clear.

Action-reaction pairsForce pairs
šŸ• 1–2 daysOpen →
EP.2.4

Newton's First Law

Objects don't want to change how they're moving. That stubbornness has a name: inertia.

InertiaEquilibriumNet force = 0
šŸ• 1–2 daysOpen →
EP.2.5

Newton's Second Law

The single most important equation in this entire course. Everything else is just plugging into F = ma.

F = maNet forceAcceleration
šŸ• 2–3 daysOpen →
EP.2.6

Gravitational Force

Why everything falls at the same rate, and how weight is just gravity wearing a different name.

WeightFree fallg ā‰ˆ 10 m/s²
šŸ• 1–2 daysOpen →
EP.2.7

Kinetic and Static Friction

The force that ruins every 'frictionless' assumption — and the one that lets you actually walk.

Static frictionKinetic frictionμ coefficients
šŸ• 2–3 daysOpen →
EP.2.8

Spring Forces

Push or pull a spring and it pushes back proportionally. One simple law explains an enormous amount of physics.

Hooke's LawSpring constantRestoring force
šŸ• 1–2 daysOpen →
EP.2.9

Circular Motion

The season finale. Every earlier idea in this unit comes together to explain why things move in circles.

Centripetal forceCentripetal accelerationNet force toward center
šŸ• 2–3 daysOpen →
šŸŽ“ AP Classroom — Progress Check 2
The heaviest-weighted unit on the exam. Covers all 9 episodes.
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