Could be a disc brake rotor, pulley.
A merry-go-round rotates because it spins on an internal axis. But the child on the merry-go-round revolves about the axis
A perfectly round plane figure is called a circle. It is defined as the set of all points in a plane that are equidistant from a fixed central point, known as the center. The distance from the center to any point on the circle is called the radius.
a sphere
Circular objects are shapes with a round outline, like wheels, plates, coins, and clocks. They have a consistent curvature around a central point, making them symmetrical in all directions.
It is a round plane figure whose boundary (the circumference) consists of points equidistant from a fixed point (the center).
I guess you cannot. Even if the object is firmly nailed down, it is in motion because the Earth is in motion - rotating about its axis and revolving around the sun. And then the sun is whizzing through space, in its path around the galactic centre, and the Milky Way Galaxy is moving towards the Andromeda cluster, and ...The only thing that you can do is to select a point of reference , which you consider a fixed point of reference and, if the location of the object with respect to that fixed point changes, then it is in motion.
A merry-go-round, or carousel, operates using a central axis that rotates around a fixed point. When the mechanism is powered, usually by an electric motor or manual propulsion, the platform spins, allowing riders mounted on seats or animals to move in circular motion. The design often includes a series of poles or arms that connect the seats to the central structure, ensuring stability and safety as it turns. Riders experience the thrill of spinning while being gently lifted and lowered, creating a fun and enjoyable experience.
Winding or coiled round; curved into a circle; taking a circular course., To revolve round a central point; to move spirally about an axis, as a tornado; to revolve.
pulleys
A wheel is a round device to roll a vehicle on. The wheel rotates around the axle which is fixed to the vehicle.
The pivot point of a lever, also known as the fulcrum, is the point around which the lever rotates or pivots when a force is applied to one end of the lever. It is the fixed point that allows the lever to amplify force or distance. The position of the fulcrum relative to the points where the force is applied and where the load is placed determines the mechanical advantage of the lever.
In a merry-go-round, the wheel and axle system allows for smooth rotation around a central point. The axle is the central rod that supports the platform, while the wheel is the circular part that enables the platform to turn easily. This design reduces friction and helps distribute the weight of riders evenly, making it easier for the merry-go-round to spin. Overall, the wheel and axle facilitate the motion and enhance the fun of the ride.