Frictional Force definitions

Frictional Force

Force acting on wind near the Earth's surface due to frictional roughness. Causes the deceleration of wind.
Found on http://www.physicalgeography.net/physgeoglos/f.html

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frictional force

the force caused by friction
Found on https://sciencetrek.org/sciencetrek/topics/force_and_motion/glossary.cfm

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