A Level PE - Angular Motion

  • Created by: hotzmc
  • Created on: 31-12-17 01:24

A Level PE - Angular Motion:

Angular Motion:

Angular Motion: Movement of a body or a body part in a circular path about an axis of rotation

  • E.g. a gymnasts whole body will rotate around the bar (axis of rotation), an athletes legs will rotate around the hip joint as the run
  • Angular motion results from an eccentric force being applied to a body where the force is applied outside the centre of a body’s mass
  • An eccentric force is also known as a torque - a turning or rotational force

Angular Motion Descriptors:

  • Angular displacement
  • Angular velocity
  • Angular momentum
  • Angular acceleration


Angular Displacement:

Angular Displacement: The angle through which an object moves on a circular path

  • It is measured in units of radians 
  • 1 radian (r) = 57.3o
  • Angle = Arc length/radius or arc = l/r

Angular Velocity:

Angular Velocity: The rate of change in angular displacement

  • Measured in radians per second (rate of spin)
  • Angular velocity = angular displacement /time taken
  • E.g. A trampolinist performing a seat drop rotated their legs clockwise about the axis 1.57 radians in 0.5 seconds. The average angular velocity is 3.14 rad/s (1.57 rad/0.5s)

Angular Momentum:

Angular Momentum: The quantity of angular motion possessed by a body

  • It is the rotational equivalent of momentum
  • Angular momentum = moment of inertia x angular velocity
  • It’s measured in kilograms metres squared radians per second (Kgm2


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