1. MECHANICAL SYSTEMS Friction & Technology (P .106)
SPH4C COLLEGE PHYSICS
MECHANICAL SYSTEMS
Friction & Technology (P .106)

2. Friction and Technology

3. Friction and Technology-Car Tires

4. Friction and Technology-Car Tires

5. Friction and Technology-Car Tires

6. Friction and Technology- Brakes

7. Friction and Technology- Brakes

8. Friction and Technology- Brakes

9. Friction and Technology- Brakes
PRACTICE
1. Discuss the validity of the statement: “Car brakes slow the wheels down but friction from the road slows the car down.”
this is true – brakes can stop/slow the wheels, however, without friction between the tires and the road, the car would never slow down/stop (i.e. hydroplaning)

10. Friction and Technology- Traction Control

11. Friction and Technology- Traction Control

12. Friction and Technology-Footwear Design

13. Friction and Technology-Footwear Design

14. Friction and Technology-Footwear Design
PRACTICE
2. (a) Why do skates slide so easily over ice?
(a) the water on top of the ice reduces the coefficient/force of friction
(b) Why will skates not slide as easily over extremely cold ice?
(b) as the ice gets cooler the layer of water gets thinner
(c) Why is the bottom of a skate curved?
(c) the edges help the skater dig into the ice to accelerate

15. Friction & Technology – Bearing Design

16. Friction & Technology – Bearing Design
PRACTICE
3. The ancient Egyptians used rolling logs to move large blocks of stone when building the pyramids. Why?
the logs served the same purposes as bearings used today – they changed the sliding friction to rolling friction which made it much easier to move the massive stones

17. Friction & Technology – Prosthesis Design

18. Friction & Technology – Prosthesis Design

19. Friction & Technology – Prosthesis Design
PRACTICE
4. A common use of prostheses today is the artificial hip. What characteristics do you think the materials used in a hip replacement must have to be able to function properly?
the material must have a very low coefficient of friction to help reduce the wear on the hip joint

20. Friction & Technology – Material Design

21. Friction & Technology

22. Check your Understanding
TEXTBOOK
P > INV.1.10 (Measuring the Coefficients of Friction)
Steps 1-5
Analysis (b),(d),(f)