Specific relative angular momentum

Imagine you are holding a toy airplane and spinning it around your finger. As it spins, you can see that it travels in a circle around your finger. The distance from the center of the circle to the toy airplane is the radius of the circle.

Now, let's pretend that the toy airplane has weight and is orbiting around a planet. The distance from the center of the planet to the airplane is called the radius of the orbit.

The toy airplane has angular momentum because it is spinning around its axis, and it also has a specific relative angular momentum because it is orbiting the planet.

Specific relative angular momentum is a measure of how fast an object is rotating or spinning as it moves around another object. It takes into account the object's mass, speed, and distance from the center of the planet it is orbiting.

In short, specific relative angular momentum is how fast and in what direction an object is both spinning and orbiting at the same time.