A 500 kg car, moving with a velocity of `36 km h^(-1)` on a straight road undirectionally, doubles its velocity in one minute. The power delivered by the engine for doubling the velocity is 

Options

A. 750 W
B. 1050 W
C. 1150 W
D. 1250 W

Answer

D

Explanation

`u = 10 ms^(-1), v = 20 ms^(-1)`
According to work energy theorem
Work done = change in kinetic energy = `1/2 mv^2 - 1/2 m u^2`
`= 1/2 xx 500 [20^2 - 10^2] = (500 xx 30 xx 10)/(2)`
The power delivered by the engine is
`P = (500 xx 30 xx 10)/(2 xx 60) W = 1250 W`