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Old 07-27-2009, 09:29 AM   #302
Sy Labthavikul
Dojo: Aikido Academy USA of Alhambra
Location: Los Angeles area, CA
Join Date: Jul 2007
Posts: 98
United_States
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Re: Is It Missing In Everybody's Aikido?

Quote:
These two vectors would tilt the refrigerator's top away from me and lift the bottom of the refrigerator nearest me off of the floor reducing the surface area the refrigerator has with the floor thus reducing the amount of friction needed to overcome.
Sorry to sidetrack, but this misconception is one of my pet-peeves. Frictional forces are completely independent of surface areas between two objects. While smaller surface area between two objects would reduce the source of frictional forces, it also INCREASES the pressure between the two objects for a given force holding them together. Since pressure equals force divided by the area of contact, it works out that the decrease in friction generating area is EXACTLY offset by the increase in pressure; the resulting frictional forces, then, are dependent only on the frictional coefficient of the materials and the FORCE holding them together.

Back to your normally scheduled program.


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