Full Mock 3 — Energy and Momentum Focus
Full Mock 3 for AP Physics C: Mechanics focuses on energy and momentum. Practice work integrals, center of mass derivations, impulse calculations, and collision analysis.
Work Integrals, Center of Mass, and Collision Analysis
Full Mock 3 targets Units 3 and 4 of AP Physics C: Mechanics — Work/Energy/Power and Linear Momentum — with elevated question frequency and difficulty in these areas across both the MCQ and FRQ sections. Students who have completed the 50% sectional test and identified energy or momentum weaknesses will find Mock 3 particularly valuable.
Emphasis Areas in Full Mock 3
Work Integrals for Variable Forces
Multiple-choice questions in Mock 3 frequently present a force function F(x) and ask for the work done over a specified displacement. These require evaluating a definite integral, and the force functions chosen — square-root functions, rational functions, trigonometric forces — are designed to test integration technique rather than simple power-rule application. Questions also test the ability to derive F(x) from a given U(x) by differentiation.
Center of Mass Calculations
FRQ components in Mock 3 require setting up and evaluating center-of-mass integrals for continuous mass distributions. Problems may involve a uniform rod, a non-uniformly dense rod with a specified density function λ(x), or a two-dimensional lamina requiring a double-integral approach simplified by symmetry. The key skill is correctly expressing dm in terms of the spatial variable before integrating.
Collision and Momentum Analysis
Mock 3 includes multi-part problems where a collision (momentum conservation) is followed by subsequent translational or rotational motion. Students must identify the collision phase, apply momentum conservation to find post-collision velocities, and then switch to energy or dynamics methods for the subsequent motion. Distinguishing elastic from perfectly inelastic collisions in context is required.
Calculus Skills Highlighted in Mock 3
- Evaluating definite integrals of non-trivial force functions for work calculations.
- Differentiating U(x) to recover the force function and vice versa.
- Setting up center-of-mass integrals with correct dm expressions and integration limits.
- Applying definite integrals of force-time functions to compute impulse.
FRQ Preparation Tips for Mock 3
For center-of-mass FRQ problems, always begin by drawing a diagram, labelling the coordinate axis, and writing the general formula before substituting. Examiners reward the setup as much as the final integral evaluation.