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Quantities, units and symbols

It is most important that when you write down a quantity you give it the correct units and use the correct symbol for those units. The following table shows most of the common quantities.

Quantity measured Name of unit Symbol of unit
Length (L) metre m
Mass (m) kilogram kg
Time (t) second s
Velocity (v) metres per second m/s
Acceleration (a) metres per second per second m/s2
Momentum newton second Ns
Force (F) newton N
Energy joule J
Power watt W
Density (ρ) kilograms per metre cube kg/m3
Pressure (P) Pascal, newtons per square metre Pa, N/m2
Frequency (f) hertz Hz
Temperature degrees centigrade, kelvin oC, K
Specific heat capacity joules per kilogram per oC J/kgoC
Specific latent heat joules per kilogram J/kg
Charge (Q) coulomb C
Current (I) amp, ampere A
Voltage (V) volt V
Potential difference (p.d) volt V
Resistance (R) ohm Ω


 
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© Keith Gibbs 2020