What force acts on a vehicle when navigating a curve?

When a vehicle navigates a curve, centripetal force is the key factor acting on it. This force acts towards the center of the curve, allowing the vehicle to change direction and continue on a curved path. As the vehicle enters a curve, the tires exert friction against the road surface, which provides the necessary centripetal force to keep the vehicle on the intended path. Without this force, the vehicle would continue in a straight line due to inertia.

Inertia, while present, describes the tendency of the vehicle to maintain its current state of motion rather than directly influencing navigation through a curve. Centrifugal force is often referred to in discussions about curved motion, but it is a perceived force that one feels when turning; it does not act on the vehicle, but rather describes the effects of inertia being experienced by the occupants within the vehicle. Gravitational force, while always acting on the vehicle, does not play a direct role in the lateral movement required for navigation around a curve.

Thus, centripetal force is the crucial and correct answer, as it is this force that actively helps maintain the vehicle's curved trajectory.