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• CGS: centimetre-gram-second.
• FPS foot pound seconds
• MKS: metre-kilogram-second.
• fundamental physical quantity
• fundamental physical quantity : independent of any other quantites
• • derived quantites: dependent on fundmental quantities
• phy quantity = numeric value * unit
• plane angle : L of arc/r of arc
• solid angle: A( surface area)/ r^2
• sig.fig: digits in a measured quantity that is reliable and certain plus one uncertain digit
• • 7 fundamental units :Mass(m)
  • Time(t)
  • Length(l)
  • , current (A)
  • amount of substance(mol)
  • luminous intensity(ca)
  • temp (K)
• Area: L^2
• Vol L^3
• speed/velocity LT^-1
• acceleration LT^-2
• momentum mv = MLT^-1
• force MLT^-2
• work force*displacement

  ML^2T^-2
• energy ML^2T^-2
• Power ML2T^-3
• pressure ML^-1T^-2
• G gravitational constant

  M^-1L^3T^-2