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Al Tobias (wat4y) - Office: Gibson S123 & Physics 218, (434) 924-0538

Physics Demo Manual

Demonstrations are cataloged according to PIRA Bibliography


Due to Physics Building renovations, the lead time to set up demo requests has increased due to the need to transport equipment across campus. Please be kind and let me know well ahead of time what you need.

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 Motion In One Dimension
 Motion In Two Dimensions
 Newton's First Law
 Newton's Second Law
 Newton's Third Law
 Statics Of Rigid Bodies
 Applications Of Newton's Laws
 Work and Energy
 Rotational Motion
 Rotational Inertia Rods
  video  - Rolling Objects and Moments of Inertia
  video  - Moment of Inertia Wheel
  video  - The Falling Rigid Body
  video  - Vector Nature of Angular Momentum
 Hero's engine
  video  - Precession of Bicycle Wheel Under Gravity Force
 Suitcase Gyro
 Air Gyro
 Euler's Disk
 Tippe Top
 Properties of Matter

 video  - Moment of Inertia Wheel


To demonstrate the effects of different distribution of mass about a fixed axis.


centered image
  DEMO VIDEO DOWNLOAD - horizontal  

centered image
  DEMO VIDEO DOWNLOAD - vertical  

The wheel is equipped with sliding weights that can be moved along the slots by loosening them with a counter-clockwise twist. Place the free weights on a holder and attach this to the string wound around the axis. Allow the weights to turn the wheel and time their descent with the masses on the wheel in both the close and far away positions.


  • Make sure string is securely attached thru hold on axis of wheel.
  • The moment of Inertia of the wheel alone is .17 kg m^2.
  • The masses are 1 kg each.
  • At the inner position, the masses are 7.0 cm from the center.
  • At the outer position, the masses are 29.5 cm from the center.


  • Timer
  • Plexiglass Inertia Wheel
  • Stand
  • Weight Holder
  • Weights