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Motion System Design
Fun With Fundamentals: Problem 260

Fun With Fundamentals: Problem 260

Can you solve this groovin’ problem in record time?

Problem 260: Extended play

More than fashionably late to the Spring sock hop, Jimmy runs up to his buddy Bobby Ray, who’s playing DJ.

“Bobby Ray! The new Twistphonics album — I got the last copy at the five and dime!”

“Coo-ool! Let’s give it a spin,” Bobby says. When the record starts playing, Jimmy winces and says, “Boy, that player sure does sound scratchy. You should get a new needle. Sounds like this one’s about to go.”

“No way! That needle could play down a record groove 100 miles long and still not break,” Bobby shouts over the Twistphonics’ latest bubble gum melody.

Given a 12-in., 33 1/3 rpm record with a 1/64 in. wide groove running from the outside edge to 2 in. from the center, what is the minimum number of times Bobby Ray would have to play one side of the record to back up his claim?

Solution to problem 259, July, 2002: Licorice whip lash

Winners circle

Fun problem 258: Pandora’s present June, 2002
Total entries: 18
Number correct: 4 (22%)
Winner: Dan Jones, Glenville, N.Y.
Dan’s prize: The Fluke 179 multimeter is designed for demanding industrial environments with a CAT IV rating, 6,000 count resolution, 0.09% accuracy, and the ability to measure min/max/average, true-rms, ac voltage, current, and temperature.

Get your creative juices flowing and send us your original problems and solutions.

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Fun With Fundamentals: Problem 259

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