When a ball rolls on a smooth level ground, the motion of its center is
Answer Details
When a ball rolls on a smooth level ground, the motion of its center is translational. Translational motion is when an object moves without rotation, i.e., when all parts of the object move through the same distance and direction at the same time. In the case of a rolling ball, the ball rotates about its own axis while also moving in a straight line. However, the motion of the center of the ball is only in a straight line, without any rotation.
This is because the center of the ball is the point at which the ball's motion is purely translational. The other points on the ball's surface, except for the point in contact with the ground, are also moving in a circular path, which is a combination of translational and rotational motion.
Therefore, the correct answer is option A: translational.