Our Dynamic Universe

• Scalar quantities


  Have only magnitude (size)
• Scalar quantities


  • Distance
  • Speed
  • Time
  • Power
  • Energy
• Scalar quantities change


  When their magnitude changes
• Vector quantities


  Have both magnitude (size) and direction
• Vector quantities


  • Displacement
  • Velocity
  • Acceleration
  • Force
  • Weight
  • Momentum
• Vector quantities change


  When their magnitude changes<|>When their direction changes<|>When their magnitude and direction both change
• Geostationary satellite


  Orbits a planet at the same rate as the planet
• Satellite


  Body that orbits a planet
• The difference in two scalar quantities = large value - small value
• The difference in two vector quantities = final vector - initial vector
• Scalar quantity


  A quantity that has magnitude but no direction
• Vector quantity


  A quantity that has both magnitude and direction
• Quantities in equations of motion

  • Initial velocity (u)
  • Final velocity (v)
  • Acceleration (a)
  • Time (t)
  • Displacement (s)
• Equations of motion


  1. v = u + at

  2. s = ut + 1/2at^2

  3. v^2 = u^2 + 2as

  4. s = (u + v)/2 t
• The equations of motion can only be used for an object travelling in a straight line with a constant acceleration
• Remember to make vectors going in one direction positive and vectors in the opposite direction negative