Physics

Fluids and optics

Pressure, buoyancy, Bernoulli, lenses, interference.

Basics

Hydrostatics

In a static fluid, pressure rises with depth. Pascal: a pressure change in a confined fluid is transmitted. Archimedes: buoyancy equals the weight of fluid displaced.

Flow

Continuity: for incompressible flow, A v is constant. Bernoulli: height, speed, and pressure trade like energy (ideal, inviscid). Real pipes add viscous and turbulent loss.

Geometric optics

Reflection: angle in equals angle out. Refraction is Snell. Thin lenses: convex converge to a real image; concave usually diverge to a virtual image. Image distance from the lens equation.

Formulas

Hydrostatic pressure

P = P₀ + ρ g h

At depth h. For water ρ≈10³ kg/m³.

Symbols

P₀ surface pressure
h depth

Buoyant force

F_b = ρ_fluid V_displaced g

To float, average density must be less than the fluid’s.

Symbols

V_displaced displaced volume

Bernoulli

P + ρ g h + ½ ρ v² = 상수

Same streamline; steady, inviscid, incompressible. Faster flow → lower pressure.

Thin lens

1/f = 1/s + 1/s′, m = −s′ / s

Object s, image s′, focal length f. Watch the sign convention.

Symbols

f focal length
m lateral magnification

Young double slit

Δy = λ L / d

Fringe spacing. Longer λ or smaller slit separation widens the pattern.

Symbols

L screen distance
d slit separation

In this field

Mechanics

Kinematics, Newton, momentum, circular motion.

Energy and work

Work, kinetic and potential energy, power, conservation.

Waves and thermodynamics

Oscillation, waves, sound, heat, entropy.

Electromagnetism and modern physics

Charge, fields, basic circuits, photons, mass–energy.

Relativity and nuclear sketch

Time dilation, length contraction, decay, cross-section.

Quantum sketch

Photons, matter waves, uncertainty.

Gravity and orbits

Newton's gravity, Kepler, surface g, and circular orbits.

Rotation

Angular velocity, moment of inertia, torque, angular momentum, rolling.

SHM and resonance

Springs and pendulums, energy swap, damping, driving, and resonance.

Electrostatics

Coulomb force, electric field, potential, and a Gauss-law sketch.

Magnetostatics

Lorentz force, Biot–Savart, Ampère, and the solenoid.