Newton's Laws of Motion: Law of Inertia - G8 Q1 M3

• Experiences of riding a car

  • Car exhilarates abruptly, making you feel as if your body is pulled to the back
  • Driver suddenly steps on the brakes, and you feel the seat belt tighten
• Newton's first law of motion

  The law of inertia, which explains how an object responds to changes in motion
• Force


  Any push or pull that causes changes in the motion of an object
• Types of force


  • Contact force
  • Non-contact force
• Contact force


  Present when two or more surfaces or media touch and interact
• Friction


  A specific type of contact force, the object's resistance to motion
• Non-contact force


  Constantly present in nature and does not need human intervention to arise
• Non-contact force


  • The sun and planets exerting a gravitational pull on each other despite their large spatial separation
• Aspects of motion


  • Speed
  • Velocity
  • Acceleration
• Speed


  The length of distance traveled in a certain amount of time
• Velocity


  The rate of change of displacement of an object
• Acceleration


  The rate of change of velocity of an object
• Motion examples


  • Car going 100 miles per hour (speed)
  • Car going 100 miles per hour east (velocity)
  • Car slowing down at the stop sign, then speeding up (acceleration)
• Newton's first law of motion


  The response of an object to changes in motion
• Parts of Newton's first law of motion

  • An object at rest will remain at rest unless acted on by an unbalanced force
  • An object in motion continues to move with the same velocity unless acted on by an imbalanced force
• Inertia


  The property that resists the changes in an object, independent from external force and mass-dependent
• Inertia examples


  • Box at rest, acted upon by normal force and gravitational force (balanced forces)
  • Spacecraft in space, with engines turned off (constant speed and direction)
  • Riding a car, experiencing sudden stop (inertia keeps you moving)
• Activity with coin, glass, and cardboard

  1. Arrange setup, slowly pull cardboard

  2. Arrange setup, quickly flick cardboard
• An object at rest will remain at rest, and an object in motion will remain in motion, unless acted on by an unbalanced force