Define watt. Express kilowatt in terms of joule per second. A 200 kg car engine develops 500 W for each kg. What force does it exert in moving the car at a speed of 20 m s–1?


One watt is the power of work done per unit time.


1 P = 1 J / 1 s .


1 kilowatt = 1000 J s–1


For 1 Kg power developed = 500W


Total Power for 200 kg = 200 × 500 = 1 × 104 W


Velocity of the car = 20m/s



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