what is the work to be done to increase to increase the velocity of a car from 72km/h to 90km/gif the mass of the car is 2400kg
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Answer:
Work done (w) = Kinetic energy (k.e.)
= 1/2 mv² - 1/2 mu²
= 1/2 m ( v²- u² )
The mass of a car = 2000kg
Initial velocity (v) = 72km/h
= 72 × 5/18
= 20m/s
Final velocity (u) = 90km/h
= 90 × 5/18
= 25m/s
work done = 1/2 m (v²-u²)
= 1/2 × 2000 (20²-25²)
= 1000 (400- 625)
= 1000×225
= 225000 j (or 225000 joules)
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