Final answer:
Clarence's statement is incorrect because velocity includes both speed and direction. Even at constant speed, changing direction means the car is accelerating. Newton's first law applies when a car moves at constant velocity down a straight road because the net forces are balanced.
Step-by-step explanation:
The statement by Clarence about keeping his car at a constant velocity is incorrect because velocity refers to both speed and direction. When a car is moving around a curve, the direction of the car is continually changing, even if the speed remains constant. According to physics, any change in speed or direction constitutes acceleration. Therefore, applying Newton's laws, Clarence's car has a nonzero acceleration because its direction is changing as it goes around the curve.
In the case of a car moving at constant velocity down a straight road, Newton's first law does apply because the net forces acting on the car are balanced, resulting in no change in the state of motion. If the velocity is not constant and the car is accelerating, then there is a net force acting on it in accordance with Newton's second law.
When comparing Car A and Car B, where Car A accelerates from rest and Car B travels at constant speed, Car A will be moving faster at the checkpoint because it has been accelerating. The proposed equation V = KVO for Car A's speed at the checkpoint is incorrect because it does not account for acceleration; it suggests that the final velocity is directly proportional to the initial velocity, which is zero, this would mean Car A would also have a velocity of zero at the checkpoint, which contradicts the given condition.
Last but not least, a car parked and a car moving at constant velocity are explained by Newton's laws by acknowledging that a parked car has no net forces acting on it, and a car moving at constant velocity has no net horizontal forces acting on it, as forces are balanced in both scenarios.