## Centripetal Force

• ME5.1 Motor Governor

When placed on a motor and spun, the balls of the governor spread radially out. The idea is to show the class that in a motor, after a certain speed, the balls will be constrained to go no farther radially. This in turn will limit the maximum speed the governor allows. The balls spread radially out due to an imbalance in centripetal force.

• ME5.4 Centrifuge - Dependence on Surrounding Medium

This centrifuge consists of fishing bobbers and glass jars. Two bobbers are attached to the ends of centrifuge so that they hand vertically when not rotating and horizontally when rotating due to centripetal force. Two jars are mounted upside down on the centrifuge with a bobber in each jar. Fill the jars with water and let the bobbers float. When the centrifuge begins to spin, the water being heavier than the bobber will be forced to the radially outward face of the jar, while the bobbers being lighter will float radially in.

• ME5.5 Marble on Loop-the-Loop

As the marble goes around the loop-the-loop, centripetal force constrains the marble to the rails of the apparatus

• ME5.6 Discover Centripetal Motion Kit (PASCO)

Hold the metal tube and swing the rubber stopper overhead. The rubber stopper moves in a circular path while the other end of the string is connected to a hanging mass. Since the system is in equilibrium, the centripetal force is equal to the weight of the hanging mass.