Given data:
* The velocity of the first car is 30 km/h
* The velocity of the second car is 60 km/h
Solution:
Let m is the mass of the first car.
As given mass of the second car is half as the first car.
Thus, the mass of the second car is,
[tex]m^{\prime}=\frac{m}{2}[/tex]The kinetic energy of the first car is,
[tex]K_1=\frac{1}{2}mv_1^2[/tex]where v_1 is the velocity of the first car,
The velocity of the second car in terms of first car is,
[tex]\begin{gathered} v_2=60\text{ km/h} \\ v_2=2\times30\text{ km/h} \\ v_2=2v_1 \end{gathered}[/tex]The kinetic energy of the second car is,
[tex]K_2=\frac{1}{2}m^{\prime}v^2_2[/tex]Substituting the known values,
[tex]\begin{gathered} K_2=\frac{1}{2}\times\frac{m}{2}\times(2v_1)^2 \\ K_2=mv^2_1 \\ K_2=2K_1 \end{gathered}[/tex]Thus, the kinetic energy of the second car with 60 km/h speed is twice the kinetic energy of the first car with 30 km/h speed.
Hence, the car with 60 km/h have greater kinetic energy than the car with speed of 30 km/h.
