Concept featured in film:Friction, banked curves

DVD: Chapter 5: 0:14:35 - 0:15:49

Play Flickclip Here (Quicktime)

Summary of clip: This clip shows driver Tom Cruise talking to his coach played by Robert Duvall. His coach is complaining that Cruise constantly has to change his tires because of the way he drives. His coach makes a deal with him - run 50 laps his way and then Cruise's way and then check the tires to see which has more damage. After the 50 laps driven both ways, the tires driven like Cruise typically drives is far more worn than when he drove carefully. His coach tells him that his car is twice as heavy and his tires are half as thick as what Cruise is used to. The clip also shows them driving around the banked curves of the track.

Connection of flickclip to the concept: This clip may be used to prompt a discussion of friction. Cruise's coach informs him that his driving is ruining the tires and is causing the tires to melt and slip on the surface.

Suggestions to Teachers:

1. Suggested questions for students when viewing the clip:

a. How would this cost Cruise time?

b. Draw all forces acting on the tire at the instant the tire goes from zero velocity, to a measurable velocity. When is there a force due to static friction present? When is there a force due to kinetic friction present?

2. Application:

Have students search the Internet to find the average speed of a stock car. Ask them to solve for the angle that the track should be banked at in order for the stock car not to skid.