1.1

• Meaning of physics


  the study of matter and energy as well as phenomena happening

  around us.
• Measurement


  a method to determine the value of a physical quantity.
• Physical quantities


  • Base quantities
  • Derived quantities.
• Base quantities


  • Time
  • length
  • electric current
  • thermodynamic temperature
  • mass
  • luminous intensity
  • amount of substance
• Base quantities


  Physical quantities that cannot be defined in terms of other physical quantities.
• Derived quantities 


  A physical quantity that is derived by a combination of base quantities. Can be done by multiplication, division or both.
• Derived quantities

  • area
  • volume
  • density
  • speed
  • acceleration
• A physical quantity must be stated


  in magnitude with its unit.
• Length


  l (small L)
• Mass


  m
• Time


  t
• Th ermodynamic temperature


  T
• Electric current


  I (big i)
• Luminous intensity


  I,v (Big i with small v)
• Amount of substance


  n
• metre


  m
• kilogram


  kg
• second


  s
• kelvin


  K
• ampere


  A
• candela

  cd
• mole


  mol
• Volume


  V
• Density


  ρ
• Velocity


  v
• Charge


  Q
• Scalar quantities


  Physical quantities that have magnitude only
• Vector quantities


  Physical quantities that have both magnitude and direction.
• Scalar quantities (examples)

  • Distance
  • Time
  • Area
  • Volume
  • Length
  • Speed
  • Work
  • Energy
  • Temperature
  • Density
• Vector quantities (examples)

  • Displacement
  • Velocity
  • Force
  • Acceleration
  • Momentum