Which concept explains why a passenger in a car lurches forward when the car suddenly stops?

The correct answer is inertia. Inertia is a fundamental concept in physics that refers to the resistance of any physical object to a change in its state of motion. This means that an object at rest stays at rest, and an object in motion continues in motion at a constant velocity unless acted upon by a net external force.

When a car suddenly stops, the car experiences a rapid decrease in speed due to the application of brakes, applying a force that changes its velocity. However, the passenger inside the car is still in motion; their body wants to continue moving forward at the same speed as the car was initially traveling. Because of inertia, the passenger tends to lurch forward as the car stops abruptly. This behavior illustrates how objects with mass will maintain their current state unless a force is applied to change that state.

Understanding inertia is crucial in recognizing how forces act on objects during rapid changes in motion, and it is a key principle in explaining various dynamics in both aviation and everyday life scenarios.