Physics Formulas and SI Units Flashcards
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Physics Formulas and SI Units Flashcards
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About this deck
The deck covers the equations most high school and introductory physics courses rely on: kinematics, Newton's laws, momentum, work, energy, power, waves, pressure, density and basic circuits. The second part lists SI units and a few physical constants.
Formula cards name the relationship on the front and give the equation with its symbols defined on the back. Unit cards give the quantity on the front and the unit, symbol and base-unit breakdown on the back.
It is useful for GCSE, high school physics, AP Physics 1 and the physics portions of science entrance exams.
Study tips
- Always say what each symbol stands for when you recall a formula; that is where most mistakes start.
- Check equations with units. If F = ma, then a newton must equal kg·m/s².
- Rearrange each formula on paper after you flip the card, solving for a different variable each time.
- Learn constant values to two or three significant figures; that is enough for most problems.
All 42 cards
| Front | Back |
|---|---|
| Average speed | v = d / t (distance ÷ time) |
| Acceleration | a = (v − u) / t (change in velocity ÷ time) |
| Velocity after constant acceleration | v = u + at |
| Displacement with constant acceleration | s = ut + ½at² |
| Velocity–displacement equation | v² = u² + 2as |
| Newton's first law | An object stays at rest or moves at constant velocity unless a net force acts on it |
| Newton's second law | F = ma (net force = mass × acceleration) |
| Newton's third law | For every action force there is an equal and opposite reaction force |
| Weight | W = mg (g ≈ 9.8 m/s² near Earth's surface) |
| Momentum | p = mv |
| Impulse | J = FΔt = Δp |
| Work | W = Fd cos θ (force × distance in the direction of the force) |
| Kinetic energy | KE = ½mv² |
| Gravitational potential energy | PE = mgh |
| Power | P = W / t (work ÷ time) |
| Efficiency | useful energy output ÷ total energy input × 100% |
| Density | ρ = m / V |
| Pressure | P = F / A |
| Hooke's law | F = kx (spring constant × extension) |
| Centripetal acceleration | a = v² / r |
| Newton's law of gravitation | F = Gm₁m₂ / r² |
| Wave speed | v = fλ (frequency × wavelength) |
| Period and frequency | T = 1 / f |
| Ohm's law | V = IR (voltage = current × resistance) |
| Electrical power | P = IV = I²R = V²/R |
| Charge | Q = It (current × time) |
| Resistors in series | R = R₁ + R₂ + … |
| Resistors in parallel | 1/R = 1/R₁ + 1/R₂ + … |
| Specific heat | Q = mcΔT |
| Mass–energy equivalence | E = mc² |
| SI unit of force | newton (N) = kg·m/s² |
| SI unit of energy and work | joule (J) = N·m = kg·m²/s² |
| SI unit of power | watt (W) = J/s |
| SI unit of pressure | pascal (Pa) = N/m² |
| SI unit of frequency | hertz (Hz) = 1/s |
| SI unit of electric charge | coulomb (C) = A·s |
| SI unit of potential difference | volt (V) = J/C |
| SI unit of resistance | ohm (Ω) = V/A |
| SI unit of temperature | kelvin (K); 0 °C = 273.15 K |
| Speed of light in a vacuum | c ≈ 3.00 × 10⁸ m/s |
| Gravitational constant | G ≈ 6.67 × 10⁻¹¹ N·m²/kg² |
| Elementary charge | e ≈ 1.60 × 10⁻¹⁹ C |
Frequently asked questions
›What is the difference between speed and velocity?
Speed is how fast something moves. Velocity is speed with a direction, so it is a vector.
›Is g always 9.8 m/s²?
It is about 9.8 m/s² near Earth's surface and varies slightly with location. Some courses round it to 10 m/s².
›What are the seven SI base units?
Meter, kilogram, second, ampere, kelvin, mole and candela. The newton, joule, watt and others are derived from them.
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