Lesson 1

• Measurement


  The art of comparing unknown values to a standard set of rules
• Units of measurement


  Standards in which physical quantities are expressed
• Two types of systems of units

  • Metric system
  • International System of Units (SI)
• Fundamental physical quantities


  • Length
  • Time
  • Mass
  • Temperature
  • Luminous intensity
  • Electric current
  • Amount of substance
• Derived physical quantities


  Computed using different formulas; combination of fundamental quantities
• Examples of derived physical quantities

  • Speed
  • Acceleration
  • Density
  • Work
  • Energy
• Fundamental quantities and SI units

  • Length: Meter (m)
  • Mass: Kilogram (kg)
  • Time: Second (s)
  • Electric current: Ampere (A)
  • Temperature: Kelvin (K)
  • Amount of substance: Mole (mol)
  • Luminous intensity: Candela (cd)
• Scientific notation


  Convenient and widely used method to express large and small numbers
• Significant figures


  Digits that are known with certainty plus first uncertainty
• All nonzero digits are significant (1-9)
• All zeros in between 2 significant digits are significant
• To get the significant figures

  1. Locate the decimal place

  2. Look for the first nonzero digit from left and count the no. of digit after
• If the decimal point is absent, start from the right
• Conversion of units


  The process of changing a value expressed in one type of unit to another unit
• Conversion factors for length

  • 1 km = 1000 m
  • 1 m = 100 cm
  • 1 cm = 10 mm
  • 1 in = 2.54 cm
  • 1 ft = 12 in
  • 1 mi = 1.61 km
• Conversion factors for mass

  • 1 kg = 1000 g
  • 1 g = 1000 mg
  • 1 slug = 14.59 kg
  • 1 metric ton = 1000 kg
• Conversion factors for area

  • 1 m^2 = 10.76 ft^2
  • 1 ha = 10,000 m^2
  • 1 acre = 4,047 m^2
• Conversion factors for volume

  • 1 L = 1000 mL
  • 1 gal = 3.785 L
  • 1 ft^3 = 28.32 L