A man increases the speed of his car from 10 m/s to 20 m/s on level road. The ratio of the final kinetic energy to initial kinetic energy is:

CONCEPT:

• Kinetic energy (KE): The energy possessed by a body by virtue of its motion is called kinetic energy.

\(KE = \frac{1}{2}m{v^2}\)

Where m = mass of the body and v = velocity of the body

CALCULATION:

Given that:

Initial speed (u) = 10 m/s

Final speed (v) = 20 m/s

Let the total mass is m.

\(KE = \frac{1}{2}m{v^2}\)

The ratio of final KE to initial KE is given by:

\(Ratio = \frac{\frac{1}{2}mv^2}{\frac{1}{2}mu^2} = \frac{v^2}{u^2} =\frac{20^2}{10^2}=4:1\)