Circular Motion Apparatus

Keep hands, loose clothing, and long hair away from the rotating disk and gear mechanism during operation. The 5-to-1 gear ratio means the disk rotates much faster than the hand crank. Start demonstrations at slow speeds and gradually increase rotation rate.

If demonstrating centripetal effects with objects on the disk, ensure adequate space around the apparatus and warn students that objects may be ejected at high speeds. Consider using a protective barrier or operating at lower speeds.

Purpose

A hand-cranked centrifugal machine with a 5-to-1 gear ratio demonstrates gear ratios and angular velocity multiplication. One turn of the crank produces just over five revolutions of the output spindle.

Cast-iron A-frame centrifugal machine with large hand-crank wheel at bottom, belt drive to small pulley at top of the frame, yellow warning label on base

Centrifugal machine in operation with a hand turning the large wheel; the top pulley shows motion blur from its higher rotational speed

Figure 1: The centrifugal machine at rest, showing the large hand-crank wheel, belt drive, and output spindle at top. The 5-to-1 ratio means the spindle turns five times per crank revolution.

Figure 2: The machine in operation. Motion blur on the top pulley shows its much higher angular velocity compared to the hand-cranked wheel.

Centrifugal Machine

1

Warning: Rotating Equipment Hazard

Warning: Projectile Hazard

Purpose

Safety Warnings

Warning: Rotating Equipment Hazard

Warning: Projectile Hazard

Purpose