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Question
An electric motor of power 100 W is used to drive the stirrer in a water bath. If 50% of the energy supplied to the motor is spent in stirring the water. Calculate the work done on the water in one minute.
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Solution
An Electric motor :
Power (P) = 100 watt.
Time (t) = 1 minute = 60 seconds
∴ Work done by motor = Produced energy
= P × t
= 100 × 60
= 6000 Joule
∴ Work done on water by motor = 50% of total produced energy
`=50/100xx6000`
= 3000 Joule.
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