18–23% of the AP exam. 8 key topics. 4 common errors analyzed.
Unit 3 (Work, Energy, and Power) is part of AP Physics 1 (Algebra-Based). Concept-first: understand the physical reasoning before memorizing equations — the four named FRQ types reward explanation over plug-and-chug.
These are the most frequently penalized mistakes on AP exam FRQs and MCQs. Review each before your next practice session.
Attempting to apply conservation of mechanical energy to inelastic collision scenarios where kinetic energy is converted to thermal energy — students must recognize that only momentum is always conserved in collisions, while mechanical energy conservation requires no non-conservative forces doing work
Defaulting to kinematic equations instead of energy methods for problems involving non-constant forces or asking about speed at a position rather than at a time — energy methods are often required or far more efficient
Calculating work using W = Fd without accounting for the angle between force and displacement, particularly when a force acts at an angle to the direction of motion (cosine factor omitted)
Misidentifying the zero-reference level for gravitational potential energy in multi-step problems, leading to sign errors when the object moves both above and below the chosen reference
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