|Steel on Steel||0.74||0.57|
|Aluminum on Steel||0.61||0.47|
|Copper on Steel||0.53||0.36|
|Rubber on Concrete||1.0||0.8|
|Wood on Wood||0.25 - 0.5||0.2|
|Glass on Glass||0.94||0.4|
|Waxed wood on Wet snow||0.14||0.1|
|Waxed wood on Dry snow||-||0.04|
|Metal on Metal (lubricated)||0.15||0.06|
|Ice on Ice||0.1||0.03|
|Teflon on Teflon||0.04||0.04|
|Synovial joints in humans||0.01||0.003|
Answered by: Ertan Salik, M.A. Physics, USC
Our server costs have gone up and our advertising revenue has gone down. You do the math! If you find our site useful, consider donating to keep us going. Thanks!
'Wisdom is the daughter of Experience, Truth is only the daughter of Time.'