1F30.20 • Inertia Cart

Location: Floor Demo

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

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Concepts Conveyed

• This demo shows Newton’s first and third laws of motion.
• With a sudden external force acting on the car to stop its motion, the figurine inside the car will retain its tendency of moving forward with the original velocity and fall off the car.
• With a force applied by the car on the pillow, an opposite reaction force will be applied by the pillow on the car.

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Instructions/Notes:

• Set the pillow down at the end of the track. This will act as your stopper.
• Set the figurine inside the seat on the car with legs straight. Do not push in too hard, otherwise a large velocity is needed.
• Push the car to give it an initial velocity. The car will recoil at the stopper, and the figurine should retain its velocity and continue moving forward and fly out of the seat.

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Demo Staff

• This demo uses the Howitzer and Tunnel track!
• Set up the demo on the end of the track without the foam board.
• Remove all other carts on the track.

Last updated on April 23, 2026