Further motion concepts

• Momentum


  A property linked to the motion of an object, depends on its mass and velocity, measured in kgm/s
• Conservation of momentum


  Total momentum before collision = Total momentum after collision (if no external force)
• Conservation of momentum example

  • Ball A: 2kg, 4m/s right

  Ball B: 1kg, -5m/s left

  Total momentum before: 8kgm/s + -5kgm/s = 3kgm/s

  After collision, balls stick together, total momentum after: 3kgm/s, velocity = 1m/s right
• Equations of motion


  • v = u + at

  x = (u + v)t/2

  x = ut + 1/2 at^2

  v^2 = u^2 + 2ax
• Using equations of motion


  • Check units

  2. If object is stationary, velocity is 0m/s

  3. Identify information in question, choose and write out equation before calculating
• Moment


  A turning force, calculated as force × distance
• Principle of moments