# Physics Formulas

### Physics Formulas - Mechanics

#### Kinematics Formulas

The Kinematic Equations apply to one-dimmensional motion with costant acceleration from point 1, situated d1 from a point of reference to point 2, situated d2 from the same point of reference. v1 is the velocity at point 1 and v2 is the velocity at point 2.
v2 = v1 + a·t
d2 = d1 + (v1 + v2)·t/2
d2 = d1 + v1·t + a·t2/2
d2 = d1 + v2·t - a·t2/2
v22 = v12 + 2a(d2 - d1)

Average velocity: vav = Δd/Δt
Average acceleration: aav = Δv/Δt

Rotational kinematics equations with constant angular acceleration:
ω2 = ω1 + α·t
Φ2 = Φ1 + (ω1 + ω2)·t/2
Φ2 = Φ1 + ω1·t + α·t2/2
Φ2 = Φ1 + ω2·t - α·t2/2
ω22 = ω12 + 2α(Φ2 - Φ1)

Average angular velocity: ωav = Δθ/Δt
Average angular acceleration: αav = Δω/Δt
Frequency: f = ω/2π
Period: T = 2π/ω

Relations between angular and linear variables:
l = Φ·r
v = ω·r
a = α·r

#### Dynamics Formulas

Pressure: P = F/A
Newton's Second Law: F = m·a
Force of kinetic friction: Ff = μ·N
Hooke's Law: F = -k·x
Centripetal Force: Fc = m·v2/R
Centripetal acceleration: ac = v2/R

#### Work, Energy, Conservation Laws Formulas

Work: W = F · d = Fdcos(α)
Potential Energy: PE = m·g·h
Kinetic Energy: KE = m·v2/2
Mechanical Energy: E = KE + PE
Instantaneous Power: P = F·v
The Work-Energy Theorem: W = ΔKE

#### Gravitation Formulas

Newtonian gravity formula: Fg = G·m·M/R2
Kepler's Third Law: T2/a3 = ct.

### Physics Formulas - Electricity and Magnetism

#### Electric Fields and Forces Formulas

Coulomb's Law: F = k·q1·q1/r2
Electric field of a charge q: E = k·q/r2
Work done by electric field: W = q·E·d
Electric field between two metallic plates: E = V/d

#### DC Circuits Formulas

Ohm's Law: V = I·R
Power dissipated in a resistor: P = I·V = V2/R = R·I2
Resistance: R = ρ·l/A
Equivalent resistance of series resistors: Rs = R1 + R2 +...
Equivalent resistance of parallel resistors: 1/Rp = 1/R1 + 1/R2 +...
Equivalent capacitance of series capacitors: 1/Cs = 1/C1 + 1/C2 +...
Equivalent capacitance of parallel capacitors: Cp = C1 + C2 +...

#### Magnetic Fields and Forces Formulas

Magnetic force on a moving charge: F = q(v x B) = q·v·B·sin(θ)
Magnetic force on a current carrying wire: F = I·l·B·sin(θ)
Magnetic field created by a current: B = (μo/2π)·(I/r)

### Physics Formulas - Thermodynamics

Heat added or emoved: Q = m·c·ΔT
Change in Internal Energy: ΔU = Q - W
Boyle's Law: P1V1 = P2V2
Charles's Law: V1/T1 = V2/T2
Efficiency of a heat engine(%): E = (W/Qhot)·100

### Physics Formulas - Waves and Optics

Snell's Law: n1·sin(θ1) = n2·sin(θ2)
Wave speed: v = λ·f
Velocity of light: v = c/n
Magnification: m = -di/do
Law of Reflection: θreflection = θincidence
Mirror and lens equation: 1/d1 + 1/d1 = 1/f

### Physics Formulas - Modern Physics

The energy of a photon: E = h·f
Matter wavelength: λ = h/p
Relativistic factor: γ2 = 1/(1 - v2/c2)
De Broglie Wavelength: λ = h/(mv)
Half life of radioactive material: Thalf = ln(2)/λ
Mass energy equivalence: E = mo·c2