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

DESCRIPTION: A ball is placed in the funnel and the funnel 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 bump below the track trips a lever, releasing the spring and ejecting the ball perpendicular to the track. Click your mouse on the photograph above to view an mpeg video of the action.

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

SUGGESTIONS: Precede this demonstration with C2-25: FUNNEL CART,and C2-26: FUNNEL CART WITH MASS OVER PULLEY, to set up your students for this problem.

See Question of the Week #8 for information on using this demonstration to enhance class involvement.

REFERENCES: (PIRA 1D60.15) See Demonstration Reference File for derivation of equations as well as papers describing uses for and variations of this apparatus.

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

SETUP TIME: None.