Chapter 1.1 Quantities and units - Summary Edexcel A Level Physics Student Book 1 - Physics (9PH0)

1.1 - Quantities and units
Système International (SI) units (base units)
●
Base quantity Base unit

Name Typical symbol Name Symbol

time t second s

length x, metre m
s (displacement)

mass m kilogram kg

electric current I ampere A

thermodynamic T kelvin K
temperature

amount of n mole mol
substance

luminous intensity lv candela cd
● Derived units

Quantity Name of unit Symbol Base units Derivation equations

area square metre A m2 A=L(length[m]) ×W ( width[m])

volume cubic metre V m3 V = A (area[m2 ])× H (width [m])

mass per µ kg m-1
unit length

mass per σ kg m-2
unit area

density kilogram per ρ kg m-3 m(mass [kg])
cubic metre ρ= 3
V (volume [m ])

velocity metres per v m s-1 s (distance [m])
second v=
t(time [s])

acceleration metres per a m s-2 v ( speed / velocity [m/ s])
second a=
t (time [s ])
squared

momentum p kg m s-1 p=m( mass[kg]) × v (velocity [m/s])



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