Science · Subjects

Physics

Formula reference for mechanics, waves, and electricity, plus the unit conversions that trip students up most.

Mechanics Waves Electricity Units

Motion & Forces

Mechanics formula sheet

ConceptFormula
Velocityv = d / t
Accelerationa = Δv / Δt
Kinematics (no time)v² = v₀² + 2a·d
Kinematics (position)d = v₀t + ½at²
Newton's second lawF = ma
WeightW = mg (g ≈ 9.8 m/s² on Earth)
Momentump = mv
Kinetic energyKE = ½mv²
Gravitational PEPE = mgh
WorkW = Fd·cos(θ)

Oscillation

Waves reference

ConceptFormula
Wave speedv = fλ (frequency × wavelength)
Period & frequencyT = 1/f
Speed of sound (air, ~20°C)≈ 343 m/s
Speed of light (vacuum)≈ 3.0 × 10⁸ m/s

Amplitude determines a wave's intensity (loudness/brightness); frequency determines pitch/color.

Circuits

Electricity reference

ConceptFormula
Ohm's lawV = IR
PowerP = IV
Series resistanceR_total = R₁ + R₂ + ...
Parallel resistance1/R_total = 1/R₁ + 1/R₂ + ...
Coulomb's lawF = kq₁q₂/r²

Reference

Unit conversion basics

Always track units through a calculation
Write units next to every number and cancel them like fractions - if the units left over don't match what the question asks for, a step is wrong.
SI base units to know
Meter (length), kilogram (mass), second (time), ampere (current), kelvin (temperature). Most other units are combinations of these.
Common prefixes
kilo- (×1000), centi- (×0.01), milli- (×0.001) - memorize these and you can convert almost any metric unit.

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