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Code Number:1D50.69
Demo Title: Central Forces Puzzle
Condition: Good
Principle: Forces Due To Circular Motion
Area of Study: Mechanics
Equipment:
Central forces puzzles
Procedure:
The trick of the puzzle is to see if you can get both balls in the small catch basins at the ends of the puzzle. Trying to tilt the puzzle back and forth will only allow you to catch one of the balls in the basin. However if you spin the puzzle the balls will be caught in the catch basins due to central forces acting on the balls.
The trick with the coin puzzle is to get the coin out of the holder. Tilting the puzzle back and forth will not move enough of the ball bearings out of the way to release the coin. Spinning the puzzle will move the ball bearings outward releasing the coin.
References:
- Henry Levinstein, "The Physics of Toys", TPT, Vol. 20, #6, Sept. 1982, p. 358, also a Potpourri of Physics Teaching Ideas - Toys, p. 269.
- R. Subramaniam and Toh Kok Aun, "Three-Dimensional Puzzle Helps Teach Centripetal Force", Physics Education, Vol. 39, #3, May 2004, p. 239.
- Richard Manliffe Sutton, "M-156. Centrifugal Force Puzzle", Demonstration Experiments in Physics, p. 67.
- Jodi McCullough and Roy McCullough, "Inertia with a Desk Toy", The Role of Toys in Teaching Physics, p. 4.52.
- Julius Sumner Miller, "Anti-Gravity Box", Physics Fun and Demonstrations, p. 52 - 53.
1D50.69 - University of Maryland QOTW Question #365 Part 1