Friday 9 November 2012

Physical Quantities

The Quantities Which Can be measured are called Physical Quantities.
The Following Quantities with Definition,Formula,Unit and Dimension are given below.
QuantityDefinitionFormulaUnitsDimensions
Basic MechanicalLength or Distancefundamentaldm (meter)L (Length)
Timefundamentalts (second)T (Time)
Massfundamentalmkg (kilogram)M (Mass)
Areadistance2A = d2m2L2
Volumedistance3V = d3m3L3
Densitymass / volumed = m/Vkg/m3M/L3
Velocitydistance / timev = d/tm/s
c (speed of light)
L/T
Accelerationvelocity / timea = v/tm/s2L/T2
Momentummass × velocityp = m·vkg·m/sML/T
Force
  Weight
mass × acceleration
mass × acceleration of gravity
F = m·a
W = m·g
N (newton) = kg·m/s2ML/T2
Pressure or Stressforce / areap = F/APa (pascal) = N/m2 = kg/(m·s2)M/LT2
Energy or Work
  Kinetic Energy
  Potential Energy
force × distance
mass × velocity2 / 2
mass × acceleration of gravity × height
E = F·d
KE = m·v2/2
PE = m·g·h
J (joule) = N·m = kg·m2/s2ML2/T2
Powerenergy / timeP = E/tW (watt) = J/s = kg·m2/s3ML2/T3
Impulseforce × timeI = F·tN·s = kg·m/sML/T
Actionenergy × time
momentum × distance
S = E·t
S = p·d
J·s = kg·m2/s
h (quantum of action)
ML2/T
Rotational MechanicalAnglefundamentalθ° (degree), rad (radian), rev
360° = 2π rad = 1 rev
dimensionless
Cyclesfundamentalncyc (cycles)dimensionless
Frequencycycles / timef = n/tHz (hertz) = cyc/s = 1/s1/T
Angular Velocityangle / timeω = θ/trad/s = 1/s1/T
Angular Accelerationangular velocity / timeα = ω/trad/s2 = 1/s21/T2
Moment of Inertiamass × radius2I = m·r2kg·m2ML2
Angular Momentumradius × momentum
moment of inertia × angular velocity
L = r·p
L = I·ω
J·s = kg·m2/s
ћ (quantum of angular momentum)
ML2/T
Torque or Momentradius × force
moment of inertia × angular acceleration
τ = r·F
τ = I·α
N·m = kg·m2/s2ML2/T2
ThermalTemperaturefundamentalT°C (celsius), K (kelvin)K (Temp.)
Heatheat energyQJ (joule) = kg·m2/s2ML2/T2
Entropyheat / temperatureS = Q/TJ/KML2/T2K
ElectromagneticElectric Charge +/-fundamentalqC (coulomb)
e (elementary charge)
Q (Charge)
Currentcharge / timei = q/tA (amp) = C/sQ/T
Voltage or Potentialenergy / chargeV = E/qV (volt) = J/CML2/QT2
Resistancevoltage / currentR = V/iΩ (ohm) = V/AML2/Q2T
Capacitancecharge / voltageC = q/VF (farad) = C/VQ2T2/ML2
Inductancevoltage / (current / time)L = V/(i/t)H (henry) = V·s/AML2/Q2
Electric Fieldvoltage / distance
force / charge
E = V/d
E = F/q
V/m = N/CML/QT2
Electric Fluxelectric field × areaΦE = E·AV·m = N·m2/CML3/QT2
Magnetic Fieldforce / (charge × velocity)B = F/(q·v)T (tesla) = Wb/m2 = N·s/(C·m)M/QT
Magnetic Fluxmagnetic field × areaΦM = B·AWb (weber) = V·s = J·s/CML2/QT

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