Example 11.4 What is the work to be doneto increase the velocity of a

1.	Example 11.4 What is the work to be doneto increase the velocity of a car from30 km h^-1 to 60 km h^-1 if the mass ofthe car is 1500 kg?
Answer» This is wrong answer This is also wrong i think the answer should be 156375 J. Mass of the car,m= 1500kg Initial velocity of the car = 30km/hr = 30×1000m/60 ×60s =8.33m/s Similarly,the final velocity of the car, v= 60km/hr =16.67 m/s Therefore,the initial kinetic energy of the car, E(initial) = 1/2 mu^2 =1/2×1500×8.33 52041.68 J. The final kinetic energy of the car, E(final) = 1/2 1500×16.67 =208416.68 J. Thus, the work done = change in kinetic energy = E(final) - E(initial) = 208416.68 - 52041.68 = 156375 J. sorry for inconvenience, the conversion is done wrong in previous solution. Last solution is correct

Example 11.4 What is the work to be doneto increase the velocity of a car from30 km h^-1 to 60 km h^-1 if the mass ofthe car is 1500 kg?

Answer»

This is wrong answer

This is also wrong i think the answer should be 156375 J.

Mass of the car,m= 1500kg

Initial velocity of the car = 30km/hr

= 30×1000m/60 ×60s

=8.33m/s

Similarly,the final velocity of the car,

v= 60km/hr

=16.67 m/s

Therefore,the initial kinetic energy of the car,

E(initial) = 1/2 mu^2

=1/2×1500×8.33

52041.68 J.

The final kinetic energy of the car,

E(final) = 1/2 1500×16.67

=208416.68 J.

Thus, the work done = change in kinetic energy

= E(final) - E(initial)

= 208416.68 - 52041.68

= 156375 J.

sorry for inconvenience, the conversion is done wrong in previous solution. Last solution is correct

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