Chapter: Motion and Measurement of Distances

• Story of Transport

  • Ancient Times
    • Walking on foot
    • Using animals for transport
  • Invention of Wheel
    • Revolutionized transport
    • Led to carts and animal-drawn carriages
  • Modern Era
    • Steam engine (railways)
    • Automobiles (cars, buses, trucks)
    • Aeroplanes and motorized boats

• Need for Measurement

  • Why measure?
    • To know how far an object has traveled
    • To buy clothes (size and length)
    • To build accurate structures
  • Standard Units of Measurement
    • SI Units (International System of Units)
    • Metre (m) as the standard unit of length
    • Multiples and sub-multiples: Kilometre (km), Centimetre (cm)

• Standard vs. Non-standard Units

  • Non-standard Units (Vary from person to person)
    • Hand span
    • Cubit
    • Footstep
  • Standard Units (Constant everywhere)
    • Scale / Ruler
    • Measuring tape
    • Avoids confusion and errors

• Correct Way of Measuring Length

  • Placement of Scale
    • Place the scale along the length
    • Keep it in contact with the object
  • Eye Position
    • Eye must be exactly in front of the point where the reading is taken
  • Dealing with Broken Ends
    • Avoid using a broken zero edge
    • Start measuring from another mark (e.g., 1.0 cm) and subtract it from the final reading

• Types of Motion

  • Rectilinear Motion
    • Motion in a straight line
    • Example: March-past of soldiers, a falling stone
  • Circular Motion
    • Motion along a circular path (distance from center remains same)
    • Example: Hands of a clock, point on a rotating fan blade
  • Rotational Motion
    • Spinning around a fixed axis
    • Example: A top spinning, blades of a windmill
  • Periodic Motion
    • Motion that repeats itself after regular intervals of time
    • Example: Pendulum of a clock, motion of a child on a swing