Final answer:
A person walking on a treadmill with uniform motion and constant speed is experiencing constant velocity, which means they are not accelerating and are not at rest in terms of their environment.
Step-by-step explanation:
The question pertains to understanding the motion of a person walking on a treadmill. When a person is walking on a treadmill at a uniform motion, they are moving at a constant speed and do not change direction. Therefore, this corresponds to walking with a constant velocity. They are not accelerating because there is no change in velocity, nor are they at rest because their position relative to the treadmill is changing. It's essential to distinguish between the motion relative to the treadmill and the environment; on the treadmill, the person exerts effort and moves their legs, but relative to the surrounding room, they are not changing position.