1C30.16 - Free-Fall Apparatus

Code Number:
1C30.16
Demo Title:
Free-Fall Apparatus
Condition:
Good
Principle:
Measurement of 'g'
Area of Study:
Mechanics

Disclaimer

Equipment:
20 Volts DC Power Supply, Electromagnet, Electric Timer, Switch Pad, Close-Up Lenses, Camera, Camera Power Supply, Ball Bearings, Air Track, Timing Gates and Counters, Air Cars, Behr Freefall App., Power Supply (Old Variable Type), Switch, Spark Generator and Spark Tape, Laptop and Interface, Photogate, and Picket Fence. Videotape of Objects Thrown of the Roof of Van Allen Hall.
Procedure:

Hookup is as shown using the appropriate adapters. For ease of measurement the distance between the ball bearing when it is suspended in the electromagnet and the switch pad should be 1 meter. The screws in the switch pad need to be tightened periodically to insure a good electrical contact.

Measurement can also be made by using an inclined Air track and timing the cars through a known distance.

The Behr Freefall App. needs to be carefully leveled to insure that the weight will fall at the proper distance from the wire so that good sparking is achieved.  Inserting a switch between the power supply and magnet will make it easier to turn of the magnet and allow the weight to fall.

Another way to quickly do a measurement of "g" is to drop one of the picket fences through a Photogate. Place a foam pad under the Photogate to prevent damage to the picket fence.

The video tape shows a variety of objects being thrown off the roof of Van Allen Hall. The entire 7 story drop is viewed so that you can make measurements if desired. Also, objects are dropped in pairs so that you can see their simultaneous fall.

References:
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https://www.ngs.noaa.gov/cgi-bin/grav_pdx.prl

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.