The AP Physics C exam is a significant hurdle for many students, demanding a deep understanding of complex concepts and the ability to apply them quickly and accurately. This cram sheet isn't a replacement for thorough study throughout the year, but rather a focused resource to help you solidify key concepts and formulas right before the exam. Remember, practice problems are crucial for success!
Mechanics (AP Physics C: Mechanics)
Kinematics
- Displacement (Δx): Change in position. Units: meters (m).
- Velocity (v): Rate of change of displacement. Units: meters per second (m/s). Average velocity: Δx/Δt; Instantaneous velocity: dx/dt.
- Acceleration (a): Rate of change of velocity. Units: meters per second squared (m/s²). Average acceleration: Δv/Δt; Instantaneous acceleration: dv/dt.
- Kinematic Equations (constant acceleration):
- vf = vi + at
- Δx = vit + (1/2)at²
- vf² = vi² + 2aΔx
- Δx = (1/2)(vi + vf)t
Dynamics
- Newton's Laws of Motion:
- 1st Law (Inertia): An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
- 2nd Law (F=ma): The net force acting on an object is equal to the mass of the object times its acceleration (Fnet = ma).
- 3rd Law (Action-Reaction): For every action, there is an equal and opposite reaction.
- Weight (W): Force of gravity on an object (W = mg).
- Friction (f): Force opposing motion. Static friction (fs ≤ μsN) and kinetic friction (fk = μkN), where μ is the coefficient of friction and N is the normal force.
- Tension (T): Force transmitted through a string, rope, cable, etc.
Work, Energy, and Power
- Work (W): W = Fd cosθ (F is force, d is displacement, θ is the angle between F and d). Units: Joules (J).
- Kinetic Energy (KE): KE = (1/2)mv². Units: Joules (J).
- Potential Energy (PE):
- Gravitational PE: PEg = mgh (h is height). Units: Joules (J).
- Elastic PE: PEelastic = (1/2)kx² (k is spring constant, x is displacement from equilibrium). Units: Joules (J).
- Conservation of Mechanical Energy: In the absence of non-conservative forces (like friction), the total mechanical energy (KE + PE) remains constant.
- Power (P): Rate of doing work. P = W/t = ΔE/t. Units: Watts (W).
Momentum and Impulse
- Momentum (p): p = mv. Units: kg·m/s.
- Impulse (J): J = Δp = FΔt. Units: N·s.
- Conservation of Momentum: In a closed system, the total momentum remains constant.
Rotational Motion
- Angular Displacement (θ): Change in angle. Units: radians (rad).
- Angular Velocity (ω): Rate of change of angular displacement. Units: radians per second (rad/s).
- Angular Acceleration (α): Rate of change of angular velocity. Units: radians per second squared (rad/s²).
- Relationship between linear and angular quantities: v = rω, at = rα (at is tangential acceleration).
- Moment of Inertia (I): Measure of an object's resistance to changes in its rotation.
- Torque (τ): τ = Iα = rFsinθ. Units: N·m.
- Rotational Kinetic Energy: KErot = (1/2)Iω².
Electricity and Magnetism (AP Physics C: Electricity and Magnetism)
Electric Fields and Forces
- Coulomb's Law: F = k|q1q2|/r². k is Coulomb's constant.
- Electric Field (E): E = F/q. Units: Newtons per Coulomb (N/C).
- Electric Potential (V): V = PE/q. Units: Volts (V).
- Electric Potential Energy (PE): PE = kq1q2/r.
Circuits
- Ohm's Law: V = IR (V is voltage, I is current, R is resistance).
- Power in a Circuit: P = IV = I²R = V²/R.
- Series Circuits: Rtotal = R1 + R2 + ...; I is the same throughout; V is divided.
- Parallel Circuits: 1/Rtotal = 1/R1 + 1/R2 + ...; V is the same throughout; I is divided.
- Capacitance (C): C = Q/V (Q is charge). Units: Farads (F).
Magnetism
- Magnetic Force on a Moving Charge: F = qvBsinθ (θ is the angle between v and B).
- Magnetic Force on a Current-Carrying Wire: F = ILBsinθ (L is length of wire).
This cram sheet provides a concise overview. Ensure you understand the underlying concepts and can apply these formulas to various problem types. Good luck!
