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Pulling a tablecloth out from underneath a dish
A common parlor trick is to pull a tablecloth out from underneath a dish. While the cloth is sliding out from under the dish there is a non-zero kinetic coefficient of friction between the cloth and the dish. Will the frictional force of the tablecloth acting on the dish do positive negative or no work on the dish?
Shouldn't friction do negative work since it is always in the direction opposite of motion?
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The force of friction may be in the direction opposite to the motion of the tablecloth
If you ever forget this just remember that
W = F • Δx
therefore if the force is going in the opposite direction then it is negative work.
Customer support service by UserEcho
The force of friction may be in the direction opposite to the motion of the tablecloth
If you ever forget this just remember that
W = F • Δx
therefore if the force is going in the opposite direction then it is negative work.