Final answer:
A parked semi-truck has no kinetic energy since it is not moving, whereas a car moving at 50 km/h has kinetic energy. Therefore, the car has more kinetic energy.
Step-by-step explanation:
The parked semi-truck has no kinetic energy because it is not moving; kinetic energy is the energy of motion. In contrast, a car moving at 50 km/h does have kinetic energy because it has both mass and velocity. Kinetic energy (KE) is calculated using the formula KE = \(\frac{1}{2}mv^2\), where m is mass and v is velocity. Since the semi-truck's velocity (v) is zero, its kinetic energy is also zero, therefore the car has more kinetic energy in this scenario.