# Physics Formula's

physics formula

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• Created by: marc
• Created on: 05-05-08 14:03

## Forces n Motion (1/2)

uniform acceleration: s = ut + ½at2

v2 = u2 + 2as

speed:v = s / t

acceleration: a = (v - u) / t

Force: F = ma

Weight: W = mg

density: ρ = m / V

Moment of a force: T = Fx

Torque: T = Fx

Pressure: p = F / A

work done: W = Fd

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## Forces n Motion (2/2)

kinetic energy: Ek = ½mv2

gravitional potential energy: ΔEp = mgΔh

power: P = W / t

power: P = Fv

stress: σ = F / A a= cross sectional area

Strain: ε = Δl / l

Young Modulus: E = stress / strain = σ / ε

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## Electrons n Photons (1/2)

electric current: I = ΔQ / Δt

potential difference: V = W / Q

potential difference: V = P / I

electrical resistance: R = V / I

resistivity: ρ = RA / l

power: P = I2R

power: P = R2 / I

electrical energy: W = VIt

resistors in series: R = R1 + R2 + ...

resistors in parallel: 1 / R = 1/ R1 + 1 / R2 + ...

force on a current carring conductor : F = BIl sin θ

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## Electrons n Photons (2/2)

photon energy: E = hf

photo-electric affect: hf = φ + Ek max

photo-electric affect: hf = φ + ½mv2max

de Broglie equation: λ = h / p

de Broglie equation: λ = h / mv

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## Wave properities (1/1)

refractive index: n = ci / cr

refractive index: n = sin i / sin r

refractive index: n = nr / ni

wave speed: v = fλ

double slit interference: λ = ax / D

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