AP Physics 1 · Unit 2
Newton's First Law: every key term you need
14 flashcard terms for AP Physics 1 Unit 2, written to match the course framework. Study them here, then drill them as interactive flashcards — free, no account needed.
Study this unit free →
Newton's First Law Object at rest stays at rest; object in motion stays in motion unless external force applied. Force required for acceleration (change in velocity).
Inertia Resistance to acceleration; measured by mass. Larger mass = harder to accelerate. Inertia not force; it's property of matter.
Newton's Second Law F_net = ma. Net force equals mass times acceleration. Vector equation: same direction as net force.
Mass vs Weight Mass: amount of matter (kg), constant. Weight: gravitational force (N), varies by location. W = mg.
Newton's Third Law Action-reaction: for every force, equal and opposite reaction. Forces act on DIFFERENT objects. Same magnitude, opposite direction.
Free Body Diagrams Sketch object with all forces acting on it. Arrows show magnitude/direction. Essential for solving dynamics problems.
Normal Force Force perpendicular to surface, prevents penetration. On flat surface: N = mg (if no vertical acceleration). N ≠ mg on inclines/accelerating surfaces.
Friction Forces Kinetic (sliding): f_k = μ_k·N. Static (no sliding): f_s ≤ μ_s·N. μ_s > μ_k usually. Friction opposes motion/tendency.
Inclined Planes Resolve weight: parallel component mg sin θ (down slope), perpendicular mg cos θ (into surface). Normal force N = mg cos θ.
Tension Force in rope/string; always pulls along string direction. Ideal rope: massless, inextensible. Same tension throughout if massless.
Pulleys Ideal pulley: massless, frictionless. Changes direction of tension. If pulley moves, analyze separately.
Atwood Machine Two masses connected by rope over pulley. Equations: (m₁ - m₂)g = (m₁ + m₂)a, T = 2m₁m₂g/(m₁+m₂).
Connected Objects When objects move together with acceleration, treat as system: F_net = (total mass)·a. Then analyze individual object for internal forces.
Unit 2 Summary Newton's laws: F=ma governs motion. Free body diagrams identify forces. Normal, friction, tension are common forces in problems.
Turn these into flashcards & quizzes →
Crammy is a free all-in-one study hub for AP, A-Level, GCSE, IB and test prep — flashcards, quizzes, practice exams, an AI tutor, and adaptive study sessions. Start studying free .
SAT® and AP® are registered trademarks of the College Board. ACT® is a registered trademark of ACT, Inc. None is affiliated with, sponsors, or endorses Crammy, and none has reviewed our practice material. All questions and explanations here are original. Legal & attributions .