Final answer:
The scenario where an object is not accelerating is when it is moving in a straight line at constant speed. This represents uniform motion without changes in speed or direction, unlike other options that involve changes in speed or direction which constitute acceleration.
Step-by-step explanation:
The question is asking about scenarios where an object is not accelerating. The definition of acceleration includes a change in speed or direction, or both. Let's review the options:
- Moving in a straight line at constant speed: This is an example of uniform motion where there is no acceleration. The object's velocity is constant in both speed and direction.
- Moving in a circle at constant speed: Even though the speed is constant, the direction is continuously changing, which means the object is experiencing centripetal acceleration.
- Changing direction while moving at a constant speed: Similar to the circular motion, any change in direction is a form of acceleration.
- Coming to a stop from motion: This is an example of deceleration, where the speed is decreasing, so the object is indeed accelerating.
Therefore, the correct answer is A) Moving in a straight line at constant speed, as this is the only case where the object is not accelerating.