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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
  video  - Center of Mass of Virginia
  video  - Center of Mass Toys
 Stacking Blocks
  video  - Stability Track
  photos  - Tension in a String
 Rope and Three Students
  photos  - Knot in Static Equilibrium
 Force and Tension
 The Roman Arch
 Rotational Equilibrium
  video  - Giant Yo-Yo
 Applications Of Newton's Laws
 Work and Energy
 Rotational Motion
 Properties of Matter

Rotational Equilibrium


To show that the sum of the torques is zero when a body is in rotational equilibrium.


  1. Mount plate by inserting support rod. Tie strings to holes on rim of plate. Position strings over pulleys and hang weights on ends. Calculate torques and verify that in equilibrium the sum of the torques is zero.
  2. Measure angles of forces using plumb bob as a vertical reference. By setting sum of horizontal and vertical components equal to zero, show that force exerted by axis is zero. Remove axis.


  • Meter Stick
  • Irregular Plate
  • Large Protractor
  • Plumb Bob
  • Pulley
  • Stand
  • String
  • Support w/ rod to fit in center hole
  • Weights