5.2 - Circular motion

• Angular displacement

  Ratio of arc length travelled per unit radius
• Angular velocity


  The rate of change of angular displacement
• Centripetal acceleration

  The rate of change of velocity of an orbiting object Acting towards the centre of the circle
• Centripetal force

  The force required to act on an object, to make it acclerate along an arc at a constant rate Acts towards the centre of the circle
• Instantaneous velocity

  The velocity of the orbiting object at any one position
• Where does the resultant force act in circular motion

  Toward centre of circle
• Tension at bottom of vertical circle

  mv^2/R + mg
• Tension at the top of a vertical circle

  T=mv^2/r - mg
• Why does the speed remain constant even though there is a resultant force acting on it 


  Resultant force acts 90 degrees to motion so zero work is done meaning speed is constant