which has more kinetic energy, a small sports car traveling at 30 km/hr or a large tractor - trailer…

Explanation:

Step1: Recall kinetic - energy formula

The kinetic - energy formula is $K = \frac{1}{2}mv^{2}$, where $m$ is mass and $v$ is velocity.

Step2: Analyze the given information

We know the velocity of the sports car $v_{1}=30\ km/hr$ and the velocity of the tractor - trailer $v_{2}=75\ km/hr$, but we have no information about their masses $m_{1}$ and $m_{2}$.

Step3: Determine the answer

Since we do not know the masses of the sports car and the tractor - trailer, we cannot calculate and compare their kinetic energies.

Answer:

There is not enough information to know.