Here's why:
* Velocity is a vector quantity representing the rate of change of position. In uniform circular motion, the velocity vector is always tangent to the circle, pointing in the direction of the object's motion.
* Acceleration is also a vector quantity representing the rate of change of velocity. In uniform circular motion, the acceleration vector always points towards the center of the circle. This is called centripetal acceleration.
Since the velocity vector is tangent to the circle and the acceleration vector points towards the center, they are always perpendicular to each other.
Example: Consider a car moving in a circular path at a constant speed. The car's velocity is constantly changing direction, even though its speed is constant. This change in velocity is caused by the acceleration directed towards the center of the circle. The velocity vector is tangent to the circle, and the acceleration vector points towards the center, making them perpendicular.
