Deceleration refers to negative acceleration, while deceleration force is a specific force resulting from that negative acceleration. Physicists typically prefer using the term acceleration, as they can work with negative values directly. According to Newton's law, force is calculated as mass times acceleration (F = ma), highlighting the distinction between force and acceleration. When braking in a car, the vehicle experiences deceleration, and the sensation of being pulled forward is due to the deceleration force acting on the driver. Understanding these concepts clarifies the relationship between acceleration and the forces involved.