Coefficient of friction ( µ )between some common materials:

 

Materials	µs
Glass and Glass	0.9
Glass and Metal	0.5 – 0.7
Ice and Wood	0.05
Iron and Iron	1.0
Rubber and Concrete	0.6
Steel and Steel	0.8
Tyre and Road, dry	1
Tyre and Road, wet	0.2
Wood and Wood	0.25 – 0.6
Wood and Metal	0.2 – 0.6
Wood and Concrete	0.62

 

                                                QUICK QUIZ

 

1. Which shoes offer less friction?

Ans: The smooth surface shoe offers less friction.

 

2. Which shoe is better for walking on a dry track?

Ans:  The smooth surface shoe is better for walking on a dry track.

 

3. Which shoes are better for jogging?

Ans:  The rough surface shoe is better for jogging.

 

4. Which sole will wear out early?

Ans:  The smooth surface sole will wear out early.