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College Physics Interactives: Instructors Guide
BANKED CURVE
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.
The Controls
 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.
Quick Demonstration
 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.
1. 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
 Select NORMAL FORCE in the Rear View Vectors section and observe and note why it is in the direction shown.
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
 Select STATIC FRICTION FORCE in the Rear View Vectors section and observe and note why it is in the direction
shown.
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
 Select GRAVITY in the Rear View Vectors section and observe and note why it is in the direction shown.
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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
 Deselect the NORMAL, FRICTION, and GRAVITY force vectors, then select ACCELERATION.
 Set the VELOCITY of the car to about 60 m/s. Observe and note the direction of the acceleration.
5. 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
 Select FRICTION FORCE in the Rear View Vectors section.
 Note that this force is now in the opposite direction from before. Why has this occurred?
Interactive: BANKED CURVE
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