Question

What is the work done to increase the velocity of a car from 36 kmh to 72 kmh if the mass of the car is 1500 kg? Does the work done by the force have a negative or a positive magnitude?​

Answer 1

Answer:

Initial Velocity, u=54km/hr=15m/s

Final velocity , v=72km/hr=20m/s

Mass =1500kg

Initial kinetic energy

1/2 (mu)square

1/2x1500x15x15= 168750 J

Final kinetic energy

1/2 (mv) square

1/2x1500x20x20=300000 J

So, change in kinetic energy = work done=300000−168750=131250J

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