PURPOSE: To illustrate how the tracking force and the skating force on a disk record arise.
DESCRIPTION: Looking downward on the disk, inspection of the geometry shows how the skating force on the stylus arises. This can be demonstrated by sitting the stylus (an old one, thank you!) on a flat aluminum disc with no grooves. Other forces on the stylus, tone arm, and record groove can also be discussed. Viewing from above with a TV allows easy visibility by a large group of students.
REFERENCES: (PIRA unavailable.)
EQUIPMENT: Small record player, record and aluminum blank, TV camera and monitor.
SETUP TIME: 5 min.
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