Radius of gyration

When you spin around in a circle, you move around a central point. The distance between this center point and your body is called the radius. Now, imagine a big toy spinning top. It also has a central point and spins around it. But, the top is not solid like your body, it is made up of many little parts like its handle, body, and cap. Each part has a different distance from the central point, and this distance is called the radius of each part.

Radius of gyration is a measure of how spread out or compact the mass of an object is from its central point of rotation. In simpler words, it tells you how much weight is concentrated in a single place or how much weight is spread out over a wider area. It is like finding the average distance of all the parts from the central point based on their weight.

When we know the radius of gyration, we can predict how difficult it will be to spin an object around its central point. An object with a higher radius of gyration needs more force to start or stop spinning than an object with a lower radius of gyration. For example, think of a light hula hoop, and a heavy wooden log. It would be easier to spin the hula hoop as it has more mass concentrated near its center, giving it a lower radius of gyration as compared to the log, which has its mass more spread out, making it tougher to spin.

Hope this helps!