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A 400 kg car attains a speed of 50 m/s f...

A 400 kg car attains a speed of 50 m/s from rest in 20s. The power developed in the engine will be

A

50 W

B

0.5 W

C

5 kW

D

25 kW

Text Solution

Verified by Experts

The correct Answer is:
D
Work done is the change in kinetic energy
`= 1/2 mv^2 - 1/2 m u^2`
Thus, `W = 1/2 xx 400 xx (50)^2`
`= 500000 J `
Power `P = W/t = (500000)/20`
`= 25000 W`
`= 25 kW`
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