Ball on String - Physics Demonstrations - Ball on String | Physics Undergraduate Labs

Maintain adequate clearance from people, furniture, and equipment. The ball can cause injury if contact occurs during rotation. Establish a clear safety zone before beginning. Inspect the string for wear before each use and it's attachment to the ball.

Purpose

Demonstrates centripetal force and circular motion by swinging a ball on a string in horizontal and vertical planes. Students observe how tension depends on speed, radius, and position in the orbit, and confront the common misconception that objects in circular motion experience an outward force.

Tennis ball attached to white cotton cord with knots at two positions and a loop handle at the end

Figure 1: The simple apparatus allows for demonstrations of circular motion at various radii by holding the string at different positions.

Ball on String

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Safety Warnings

Caution: Rotating Object Hazard

Purpose