A vehicle's kinetic energy is directly proportional to which of the following factors?

A vehicle's kinetic energy is directly related to its speed due to the formula for kinetic energy, which is calculated as one-half of the mass of the object multiplied by the square of its velocity (KE = 1/2 mv²). This means that as the speed of a vehicle increases, even a slight change in speed results in a significantly larger change in kinetic energy, because the velocity is squared in the equation.

While the weight or mass of the vehicle does contribute to kinetic energy, the primary factor influencing changes in kinetic energy during driving scenarios is speed. Engine power does not directly relate to kinetic energy; rather, it affects the vehicle's acceleration and top speed. Additionally, the number of passengers may alter the vehicle's total weight but does not have a direct influence on the kinetic energy in terms of how speed affects it. Therefore, the relationship between kinetic energy and speed is critical in understanding vehicle dynamics and safety measures such as stopping distances and crash impacts.