Which vehicle will have more kinetic energy, a parked semi truck or a car going 50 km/h?

A car going at 50 km/h will have more kinetic energy.

Explanation:

Kinetic energy of an object is produced when the object is in motion. It is known that kinetic energy is directly proportional to the mass of the object and also to square of velocity or speed experienced by the object.

So, a parked semi-truck will have zero kinetic energy as the speed or velocity of the semi-truck is zero. Thus, the kinetic energy will be zero for a parked semi-truck. While as there is speed for the car moving at 50 km/h, hence, it will exhibit higher kinetic energy compared to parked semi-truck.