why do the blades of an electric fan continue to rotate for some time after the current is switched off?
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Answered by
93
blades continue to rotate bcoz of the momentum gained by them , when electric current was being passed through it... therefore when u close the fan it is only due to momentum that blades continue to rotate
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Answered by
64
This is due to the first law of dynamics. by Newton Sir Isaac..
When the fan blades are in full speed, the friction is overcome by the additiona l power that the mains supply..
When the switch is off, then the momentum (angular) of the blades remains with the blades. Due to the friction acting on the blades at the center of the fan, the speed reduces slowly and gradually and then it comes to rest. Some energy in the fan wings is dissipated as heat due to friction. Some energy (in the momentum) is converted into work to rotate the blades for some more time.
If there is no friction, then the fans continue to rotate even after switching them off.
When the fan blades are in full speed, the friction is overcome by the additiona l power that the mains supply..
When the switch is off, then the momentum (angular) of the blades remains with the blades. Due to the friction acting on the blades at the center of the fan, the speed reduces slowly and gradually and then it comes to rest. Some energy in the fan wings is dissipated as heat due to friction. Some energy (in the momentum) is converted into work to rotate the blades for some more time.
If there is no friction, then the fans continue to rotate even after switching them off.
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