Picket Fence - Obtaining g

A picket fence is dropped through a photogate and a plot of velocity vs. time is displayed. The bands on the picket fence interrupt the photogate. Because the picket fence has a known band width, the sensor records the time of the interruption and calculates the velocity. The slope of this line gives the acceleration which is an experimental determination of g.

* Equipment seen in the video may vary from equipment used in ND Demonstrations. See information and images below for ND equipment and setup.

Setup:

Connect the photogate to the Pasco interface. Connect the interface to the computer. Connect the demo computer to the projector system. Mount the phtotgate to the lab table using the clamps. Open the Pasco data collection software and create a graph of velocity vs. time.

Press record on the software and drop the picket fence through the photogate. The graph populates. Press stop to end data collection. Use the linear fit to see the slope of the line and the calculated value of g.

Notes:

Be sure the picket fence does not hit the photogate.

Courses Used In:

  • PHY 10111

  • PHY 10310

  • PHY 10410

  • PHY 10320

Discussion and Polling Questions:

  • Does this experiment directly measure g? What does it directly measure?

  • Why do the lines have to be exactly the same?

Equipment Needed:

  • Demo Computer or Laptop

  • Pasco Interface

  • Photogate

  • Picket Fence

  • Clamps