[:PiraScheme#Mechanics: Table of Mechanics Demonstration]

[:MEEquipmentList: List of Mechanics Equipment & Supplies]

[:Demonstrations:Lecture Demonstrations]

Cut the String, 1D55.15

Topic and Concept:

Location:

Abstract:

Equipment

Location

ID Number

Apparatus w/Spool

ME, Bay A9, Shelf #1

1D55.15

Exacto Knife w/Adjustable Stand

ME, Bay A9, Shelf #1

1D55.15

Ball

Found w/Exacto Knife, Spares in ME, Bay A13, Shelf #3

EQ

Lead Block

Rod and Clamp Cabinet

EQ

Important Setup Notes:

Setup and Procedure:

  1. Place the apparatus on the lecture bench in desired location.
  2. Place lead block on top of apparatus to keep it in place throughout the demo.
  3. Plug in the apparatus making sure the switch is in the off position beforehand.
  4. Unwind the appropriate amount of string off the spool so that the ball can be tied as pictured above. The spool is set up as a cam. There are notches in the bottom of the spool that line up with a pin so that the length is fixed throughout the demo.
  5. To attach the ball, run the thread through both holes of the D-shaped portion of the rotating arm and tie the thread securely around the eye-hook. Lock the thread in place by pushing a small matchstick (the flammable portion removed)into one of the holes as pictured below.
  6. Place the Exacto knife in its stand on the table. Align the knife so that it cuts the thread in the D-shaped portion of the rotating arm. The stand should be placed such that when the thread is cut, the ball flies off to the right or left of the audience.
  7. The speed of rotation can be adjust using the silver knob located below the center of rotation on the apparatus.
  8. When ready, turn the apparatus on by pushing the switch into the on position.
  9. The ball will be placed into a circular trajectory. Cut the string at the desired time by raising the Exacto knife. This is done by turning the lower of the two knobs on the stand. The ball will assume a trajectory tangent to its the original circular trajectory. The point of tangency being determined by the placement of the Exacto knife.

Cautions, Warnings, or Safety Concerns:

Discussion:

attachment:Device01-250.jpg

attachment:Device02-250.jpg

attachment:Device05-250.jpg

attachment:Motor01-250.jpg

attachment:BallString01-250.jpg

attachment:Spool01-250.jpg

attachment:Ball01-250.jpg

attachment:Ball02-250.jpg

attachment:Exacto01-250.jpg

attachment:Exacto03-250.jpg

attachment:Lead01-250.jpg

Videos:

References:

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