Unit 2: Linear motion and waves

Power and efficiency. Defines $P = W/t = Fv$, derives the relationship between power and velocity for a constant force, defines efficiency as useful energy out divided by total energy in, and works the QCAA-style elevator and motor problems used in EA Paper 1.

Work and mechanical energy. Defines $W = Fs\cos\theta$, $KE = \frac{1}{2}mv^2$, $PE_g = mgh$, the work-energy theorem and conservation of mechanical energy; works the QCAA roller-coaster style problem including a friction case for the EA.

Momentum and impulse. Defines $p = mv$ and $J = F \Delta t = \Delta p$, walks through conservation of momentum in one-dimensional collisions and explosions, and distinguishes elastic from inelastic by whether kinetic energy is conserved. Works the QCAA two-cart collision standard problem.

Equations of uniformly accelerated motion. Lists the four QCAA-formulae-sheet suvat equations, the conditions under which they apply, and works the free-fall standard question that recurs in IA1 and EA Paper 1.

Newton's three laws and force analysis. States each law, walks through free-body diagrams for the standard QCAA problem types (level surface with friction, inclined plane, connected bodies, hanging tension), and works a force-on-an-incline example that recurs in IA1 stimulus and EA Paper 2.

Basic kinematic quantities. Defines position, displacement, distance, speed, velocity and acceleration; distinguishes average and instantaneous values; and works the QCAA short-answer style problem on average versus instantaneous velocity that recurs in IA1 and the EA.

Scalar and vector quantities. Defines the distinction with examples, walks through vector addition (head-to-tail and component methods), subtraction as adding the opposite, and the standard QCAA component resolution students use throughout Unit 2 motion and Unit 3 fields.

Motion graphs. Reads slope and area on position-time, velocity-time and acceleration-time graphs; converts between them; and works the QCAA-style multi-phase journey problem that recurs in IA1 stimulus and EA Paper 1.

Wave equation $v = f \lambda$. Reviews the algebra, applies it across mechanical and electromagnetic waves, and works the QCAA-style question on what happens to wavelength when a wave passes from one medium to another (frequency unchanged, speed and wavelength scale together).

Superposition and interference. States the principle of superposition, links constructive and destructive interference to path-length difference and phase, and works the QCAA-style two-speaker interference problem from EA Paper 2.

Properties and types of mechanical waves. Defines wavelength, period, frequency, amplitude and speed, distinguishes transverse (string, water surface, electromagnetic) from longitudinal (sound, P-waves) and works the QCAA-style identification question that recurs in EA Paper 1 multiple choice.

Standing waves and resonance. Derives the resonant-frequency series for a string fixed at both ends, an open pipe (both ends open) and a closed pipe (one end closed), and works the QCAA-style guitar-string and organ-pipe problems from EA Paper 1 and Paper 2.

QCE Physics Unit 2 subject-matter point on linear motion. Kinematics (suvat), Newton's three laws, momentum and impulse, work, kinetic and potential energy, conservation of energy, and power; foundation for Unit 3 Newtonian motion in 2D.

QCE Physics Unit 2 subject-matter point on waves. Wave properties and wave equation $v = f\lambda$, transverse vs longitudinal, sound waves and their properties, wave behaviours, Doppler effect, and the electromagnetic spectrum.