Purpose
This interactive uses a car on a banked curve as an application of friction and other important forces.

Using the Interactive

• Configure the interactive using the CONTROLS template on the right-hand side.
• The left-hand side shows a circular banked track around which a car travels. In the center of the track is a rear view of the car on which certain vectors can be displayed.

• Velocity: This slider controls the tangential speed of the car.
• Track Incline: This slider controls the angle that the track makes with the horizontal.
• Friction: This controls the coefficient of static friction between the tires and the track. For race cars, this coefficient is often quite large.
• Play/Pause: This button animates the motion of the car around the track.
• Step: This button animates the motion one step at a time.
• Overhead Vectors: Provides options for displaying velocity and acceleration vectors on the overhead view of the car.
• Rear View Vectors: Provides options for displaying various vectors on the rear view of the car.

1			After starting the interactive, set TRACK INCLINE (39°) to the largest angle, set FRICTION to the largest coefficient (6.0), and deselect VELOCITY from the Overhead Vectors section. Direct your attention to the rear view. In what direction is the normal force on the car?
			A)	perpendicular to the track pointing upward.
			B)	perpendicular to the track pointing downward.
			C)	parallel to the track pointing down the incline.
			D)	parallel to the track pointing up the incline.
			E)	vertically downward.
			F)	vertically upward.
			G)	horizontal
2			In what direction is the force of friction on the car?
			A)	perpendicular to the track pointing upward.
			B)	perpendicular to the track pointing downward.
			C)	parallel to the track pointing down the incline.
			D)	parallel to the track pointing up the incline.
			E)	vertically downward.
			F)	vertically upward.
			G)	horizontal
3			In what direction is the gravitational force on the car?
			A)	perpendicular to the track pointing upward.
			B)	perpendicular to the track pointing downward.
			C)	parallel to the track pointing down the incline.
			D)	parallel to the track pointing up the incline.
			E)	vertically downward.
			F)	vertically upward.
			G)	horizontal
4			Once motion begins, in what direction will the acceleration of the car be?
			A)	perpendicular to the track pointing upward.
			B)	perpendicular to the track pointing downward.
			C)	parallel to the track pointing down the incline.
			D)	parallel to the track pointing up the incline.
			E)	vertically downward.
			F)	vertically upward.
			G)	horizontal
5			Set the VELOCITY of the car to about 60 m/s. In what direction is the force of friction on the car?
			A)	perpendicular to the track pointing upward.
			B)	perpendicular to the track pointing downward.
			C)	parallel to the track pointing down the incline.
			D)	parallel to the track pointing up the incline.
			E)	vertically downward.
			F)	vertically upward.
			G)	horizontal