Uniform linear motion is motion at a constant speed in a constant direction.
Uniform circular motion is motion at a constant speed, in a direction that's changing at a constant rate. To be honest about it, the direction vector makes a complete revolution for every revolution of the object in motion.
Uniform linear motion involves moving at a constant speed along a straight path with no change in direction, while uniform circular motion involves moving at a constant speed in a circular path, requiring continuous change in direction. This results in centripetal acceleration in circular motion. Both types of motion differ fundamentally in their path and how they influence velocity.
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