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CLIP 13191

Centripetal force and circular motion

Centripetal force and circular motion

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Key Info
  • Centripetal force and circular motion
  • Duration: 03:02
  • Dr Yan from BBC the One series 'Bang Goes The Theory' entertains members of the public by getting them to swing a tray attached to a length of string over their heads, whilst a glass which is half full of water sits on the tray. The glass remains on the tray and the water remains in the glass. Yan explains that centrifugal force is a fictitious force and that the tension in the string provides the centripetal force that changes the direction of an object in circular motion, preventing the water from falling due to gravity. During planetary motion, centripetal force is provided by gravity. First broadcast on BBC One on 'Bang Goes the Theory' in March 2011.
  • Subject:



    Phys: Forces - Motion

  • Keywords: Circular motion, gravity, centripetal force, centrifugal force, acceleration, swing, pendulum, Dr Yan, Banggoesthetheory
Ideas for use in class
  • Could be used as an introduction to circular motion. Students can then repeat this demonstration outside, exploring the minimum rate of rotation (i.e. linear velocity) required to prevent the water from falling. This clip accompanies a BBC Teachers' Pack to support Series 3 and 4 of 'Bang Goes The Theory'. The pack can be downloaded from
Background details
  • Clip language : English
  • Aspect ratio : 16x9

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