Question

9, IF the engine of a car of mass m is capable of delivering power P, the minimum time needed for the car to accelerate from rest to a speed v is?

Answer 1

Gives

Power =p

Mass=m

Speed=v

Energy change

$∆E=\frac{1}{2}mv^2-0$

$∆E=\frac{1}{2}mv^2$

$Power (p)=\frac{W}{t}=\frac{∆E}{t}$

$P=\frac{\frac{1}{2}mv^2}{t}=\frac{mv^2}{2t}$

$t=\frac{mv^2}{2P}$