PURPOSE: To demonstrate the independence of velocity components in a dramatic way.

DESCRIPTION: A ball is placed in the launcher and the mechanism is cocked by compressing a spring. The cart is then pushed across the track. At an adjustable point along the track a sensor releases the spring trigger ejecting the ball vertically. Because the ball and the cart both move with the same horizontal speed, the ball stays directly above the cart at all times, and falls back into the launcher. Before doing the experiment, ask your students where the ball will fall: in front, behind, or in the cart.

SUGGESTIONS: Follow this demonstration with 1D60.16: HOWITZER CART WITH MASS OVER PULLEY, AND 1D60.15: HOWITZER CART ON INCLINE.

REFERENCES:

EQUIPMENT: Howitzer cart with ball on dynamics track, as photographed.

SETUP TIME: 5 Min.

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