Final answer:
The instantaneous velocity of an object moving at constant speed in a circular path is constant in magnitude but always changing in direction, resulting in a nonzero velocity whose direction is tangential to the circle at any given point.
Step-by-step explanation:
The instantaneous velocity of an object moving in a circular track at constant speed is neither maximum, minimum, nor zero; it is constant in magnitude but changing in direction. As the object moves along the circular track, the direction of the instantaneous velocity at any point is tangential to the circle. Since velocity includes direction as well as magnitude, and while the speed (scalar quantity) is constant in uniform circular motion, the velocity (vector quantity) is constantly changing because its direction changes. The constant change in direction implies there is a centripetal acceleration pointing toward the center of the circular path, which is essential for maintaining circular motion but does not affect the speed of the object.
The correct answer to the question is D. Constant. This is because, in uniform circular motion, an object travels on a circular path at a constant speed. Even though the speed is constant, the velocity is not constant due to the continuous change in direction of the instantaneous tangential velocity as the object moves along the circular path.