• Any object travelling in a uniform circular motion at the same speed travels with a?constantly changing velocity
• This is because it is?constantly changing direction, and is therefore accelerating
• The?angular speed?(?) of a body in circular motion is defined as:

The rate of change in angular displacement with respect to time

• Angular speed is a?scalar quantity?and is measured in rad s-1
• It can be calculated using:

• Where:
  • Δθ?= change in?angular displacement?(radians)
  • Δt?= time interval (s)

   

When an object is in uniform circular motion, velocity constantly changes direction, but the speed stays the same

• Taking the angular displacement of a complete cycle as 2π, the angular speed ? can be calculated using the equation:

• Where:
  • v =?linear?speed (m s-1)
  • r?= radius of orbit (m)
  • T =?the?time period?(s)
  • f?=?frequency?(Hz)

   

• Angular velocity is the same as angular speed, but it is a?vector quantity
• This equation shows that:
  • The greater the rotation angle?θ?in a given amount of time, the greater the angular velocity ?
  • An object rotating further from the centre of the circle (larger?r) moves with a smaller angular velocity (smaller ?)