A car of mass `500kg` moving with a speed `36kmh` in a straight road unidirectionally doubles its speed in `1min`. Find the power delivered by the engine.

Options

A. 1250 W
B. 1250 HP
C. 625 W
D. 625 HP

Answer

A

Explanation

Its initial speed `v_(1)=(36000)/(3600) =10ms^(-1)`
If the car doubles its speed, finally its speed becomes `v^(2) =20ms^(-1)`
Change in KE of the car `=Delta KE =(1//2)`
`mv_(2)^(2) -(1/2)mv_(1)^(2)`
During Dt = 1 min = 60 s the power delivered by the engine, `P=("Work done")/("Time taken") =(|Delta KE|)/(Delta t)`
`=((1)/(2) xx m [v_(2)^(2) -v_(1)^(2)])/(Delta t) =(1//2 xx 500 [20^(2)-10^(2)])/(60)`
`=1250 W`