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

DESCRIPTION: A ball is placed in the howitzer and the howitzer cocked by compressing a spring. The track is raised at one end so that when it is released the cart accelerates down the track. At a certain point a sensor triggers the spring mechanism ejecting the ball perpendicular to the track. You can also give the cart a shove up the incline so that the howitzer will launch while the cart is slowing.

Before doing the experiment, ask your students where the ball will fall: in front, behind, or in the howitzer.

SUGGESTIONS: Precede this demonstration with 1D60.10: HOWITZER CART,and 1D60.16: HOWITZER CART WITH MASS OVER PULLEY, to set up your students for this problem.

REFERENCES:

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

SETUP TIME: 5 Min.

	Go back to Lecture-Demonstration Home Page.
	If you have a question or comment, send an e-mail to Lecture Demonstrations Coordinator: Jerry Hester