1. SI Units Flashcards
Base Units
Second Metre Mole Amp Candela Kelvin Kg
Derived
Celsius Newton Pascal Bar Joule Watt Electron-volt Hertz Cubic metre Litre.
The SI base units, which involve the SI base quantity of length include:
Acceleration - metres per second squared (m/s2)
Area - square metres (m2)
Luminance - candela (Cd) per square metre
Volume - cubic metres (m3)
Wave number - reciprocal metres
What is the newton
& units
Derived unit of force
to move 1 kg of mass at a rate of one metre per second squared (m/s2):
F = m·a (where a is acceleration)
F = 1 kg·m/s2
What is the joule
unit
Derived unit of energy, work or amount of heat.
It is the amount of energy expended if a force of one newton (N) is applied through a distance of one metre (N·m):
J = 1 kg·m/s2·m = J = 1 kg·m2/s2 or 1 kg·m2·s-2
Velocity
Unit
Velocity is metres travelled per second (m/s or m·s-1).
What is the watt
SI Unit power
power is the watt (W) or number of joules expended per second:
J/s = kg·m2·s-2/s J/s = kg·m2·s-3
What is a pascal
Unit
Pressure is force (N) per unit area (m2) and measured is pascal (Pa):
Pa = kg·m·s-2/m2 Pa = kg·m-1·s-2
Put these small units in order
U, N, P, F, A, D, M
- 1 (10-1) - deci (d)
- 001 (10-3) - milli (m)
- 000001 (10-6) - micro (µ)
- 000000001 (10-9) - nano (n)
- 000000000001 (10-12) - pico (p)
- 000000000000001 (10-15) - femto (f)
- 000000000000000001 (10-18) - atto (a)
Force
ence that produces a change, either of movement, direction or construction
Newtons
mass.length/time2
Mass × acceleration
Pressure × area
Work / distance
½ mass × velocity2 is for measuring kinetic energy, not force.
Force equation
Force = mass × acceleration
Capacitance Eqn
Capacitance (farad) = charge / voltage
Kinetic energy eqn
Kinetic energy = ½ × mass × (velocity)².
Reynolds number = eqn
eynolds number = density × velocity × diameter / viscocity
