Final answer:
The person not wearing a seatbelt and thrown forward during sudden braking exemplifies Newton's first law of motion, highlighting the law of inertia.
Step-by-step explanation:
The scenario described in the question is an example of Newton's first law of motion, often referred to as the law of inertia. Newton's first law states that an object in motion will remain in motion with a constant velocity unless acted upon by an outside force. In the absence of a restraining force, such as a seatbelt, the person continues moving forward when the car stops abruptly due to inertia.