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The velocity of a car increase from 54km per hour to 72 km per hour. How much is the work done if the mass of the car is 1500kg? |
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Answer» Mass of CAR m = 1500 kg Initial velocity = 54 km/h = 54 X 5/18 = 15 m/s Final velocity = 72 km/h = 72 x 5/18 = 20 m/s (1 km/h = 1000 m/ (3600 s) = 5/18 m/s Initial kinetic energy = ½ mv2 = ½ x 1500 x (15)2 = 168750 J Increased kinetic energy = 1/2 mv2 = ½ x 1500 x (20)2 = 300000 J Work done = Change in kinetic energy = 300000 - 168750 = 131250 J Hence the work done by the force on the car = 131250J |
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