Question

A one-ton car moves with a constant velocity of $15m{s}^{-1}$ on a rough horizontal road. The total resistance to the motion of the car is 12% of the weight of the car. The power required to keep the car moving with the same constant velocity of $15m{s}^{-1}$ is
$[Takeg=10m{s}^{-2}]$

• A. 9 kW
• B. 18 kW
• C. 24 kW
• D. 36 kW

Answer 1

The correct option is B 18 kW

$F=R\times m\times g=\frac{12}{100}\times 1000\times 10N=1200N$
$P=Fv=1200N\times 15m{s}^{-1}=18kW$