Speed:

When an object moves in a circle with uniform speed, its speed remains constant throughout the motion. Speed is defined as the distance traveled per unit of time. In a circular motion, the object covers equal distances in equal intervals of time. Therefore, the speed of the object remains the same.

Velocity:

Velocity is a vector quantity that takes into account both the magnitude and direction of motion. When an object moves in a circle with uniform speed, its velocity is constantly changing. This is because velocity depends on both speed and direction. In a circular motion, the direction of the object is constantly changing as it moves along the circumference of the circle. Therefore, the object's velocity is not constant and keeps changing.

Acceleration:

Acceleration is the rate at which the velocity of an object changes. When an object moves in a circle with uniform speed, it experiences acceleration towards the center of the circle. This acceleration is called centripetal acceleration. The direction of centripetal acceleration is always towards the center of the circle, perpendicular to the object's velocity vector.

The magnitude of centripetal acceleration can be calculated using the formula:

a = v^2 / r

where "a" is the centripetal acceleration, "v" is the velocity of the object, and "r" is the radius of the circle. This formula shows that the acceleration is inversely proportional to the radius of the circle. Therefore, as the radius decreases, the centripetal acceleration increases.

Summary:

- In a circular motion with uniform speed, the object's speed remains constant.
- The object's velocity constantly changes because its direction changes as it moves along the circumference of the circle.
- The object experiences centripetal acceleration towards the center of the circle, which is perpendicular to its velocity vector.
- The magnitude of centripetal acceleration is inversely proportional to the radius of the circle.

When an object moves in a circle with uniform speed, it has a constant change in it’s direction. Since velocity is a vector quantity which has both magnitude and direction, constant change in object’s direction (magnitude (speed) is fixed in this case), makes velocity a varying component. Thus velocity varies at every point in the circular path.

Where as, in case of acceleration, we have only the radial acceleration which always point inward directing towards the center ( the main source to make the object undergo a circular motion by providing required centripetal force). Hence the magnitude and direction is constant, the  acceleration is as constant (non zero value) one.

If the acceleration becomes zero, centripetal force ( centripetal force nothing more than a tension that keeps the object in its circular path) required to make the circular motion becomes zero and hence the object no longer go in an circular path..