Ball in Inverted Wine Glass
Purpose
A ball orbiting inside an inverted wine glass stays up instead of falling out. Students analyze the force balance — normal force from the curved surface provides centripetal acceleration while its vertical component plus friction supports the ball against gravity.
Figure 1:
Inverted wine glass with 1.5-inch orange superball. Circle the glass to spin the ball up the curved interior; it stays inside as long as circular motion is maintained.
Demo Apparatus
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