Final answer:
The statement is true; an object accelerates when its speed changes or when it changes direction. Acceleration pertains to any change in velocity, whether increasing, decreasing, or altering direction. Negative acceleration or deceleration is opposite in direction to positive acceleration.
Step-by-step explanation:
The statement that an object accelerates when it slows down or its direction of movement changes is True. Acceleration is defined as the rate at which an object's velocity changes with time, which includes speeding up, slowing down (decelerating), and changing direction. If we consider Newton's Second Law of Motion, the presence of a net force will result in an acceleration, which can manifest as a change in speed or direction.
For example, a car turning a corner is accelerating because the direction of its velocity is changing. Similarly, when a car comes to a stop, it is also accelerating because the magnitude of its velocity is changing—in this case, decreasing. With both scenarios, acceleration is taking place.
Lastly, a negative acceleration, often called deceleration, indeed points in the opposite direction of positive acceleration. However, keep in mind that acceleration does not always point in the direction of motion. For instance, when a train slows down, it is accelerating in a direction opposite to its motion.