1D60.15 • Ball & Hinge

Photo shows the demonstration used at the University of Texas at Austin.

Concept:

• This Ball and Hinge demonstration illustrates the differences between linear and angular acceleration, and because of these differences, the hinged stick will fall faster than the steel ball due to its greater moment of inertia.
• the ball should land in the cup as the board falls simultaneously.

Instructions / Notes:

• Before each run:
  1. Make sure one of the foams inside the Dixie cup is near the top of the cup, leaving a gap of air inside
  2. Ensure the hinged board is parallel to the resting board by lifting the hinged board and leveling it by checking if the bubble is in the middle of the level
  3. Have the steel ball sit on the golf ball holder
• Procedure:Once you have done the three steps above, hold your board in place, leveled, with the ball sitting on the holder, and drop the board to the resting board.
• Since the hinged board is parallel to the resting board, the steel ball should fall straight inside the Dixie cup.

• In case of wear and tear of the Dixie cup, remove the screws from the bottom of the cup and replace them; put two Dixie cups together for better resistance to wear and tear.

Last updated on November 12, 2025