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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
  video  - Introduction to Lagrangian
 AirPro Hockey pucks
  video  - Marble and Feather
  video  - Free Fall Acceleration
  video  - Uniform Linear Acceleration - Time
  video  - Uniform Linear Acceleration - Velocity
 Propeller Cart on Track
 Measurement of Free Fall Acceleration
 Falling Drops of Milk
 Falling Ball
 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
 Properties of Matter

 video  - Uniform Linear Acceleration - Time


To verify constant acceleration down an inclined track and compute g.

Note: this is the same as demo 1C20.31 Uniform Linear Acceleration - Velocity. The Capstone software measures the time between gates #1 & #2 and #1 & #3, and the instantaneous velocity at gates #2 and #3 (four parameters total).


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  DEMO VIDEO DOWNLOAD w/ sound / 1920x1080 / 24.19Mb/s / 384MB size  

  DEMO VIDEO DOWNLOAD w/ sound / 854x480 / 5.69Mb/s / 92MB size  

Raise one end of air track on blocks of wood to provide an incline, for example 2.5cm or 5.0cm thick. Place photogates on air track so that there is 'x' distance between photogates 1 and 2, and 4x's the distance between photogates 1 and 3. Starting at Vo = 0 just in front of photogate 1, let the cart accelerate through gates and record times.

New PASCO Timers: PASCO Capstone software is installed on the Rm. 203, 204 and 205 computers. Run experiment "Uniform_Linear_Acceleration.cap" and press "Record" in lower left corner to start. For Rm. 203, Capstone software is installed on "Big Bench PC" (not the main lecture computer).

Old Unilab Timers: Drive both gate modules with the same oscillator by connecting them in parallel. Connect both 'A' gates in parallel so both timers start together. Connect photocell 1 to 'A' gates. Connect photocell 2 to 'B' gate 1 and photocell 3 to 'B' gate 2. Place gate 'A' switches in break hold position and gate 'B' switches in open position. Switches on all photocells must be in the open position. Adjust photocells by manually moving cart through beam and noting on the air track scale the exact point at which the gate operates.


Note that the cart needs to start at rest at photogate #1, as close as possible w/o triggering the gate.


  • 2 Timer Counter
  • 1 Oscillator
  • 2 Gate Module
  • 3 Photocell Modules
  • Air cart with raised paper tab
  • Air Track
  • Connecting Wires
  • 2 Divider Modules