I don’t even know really what intertia means let alone moment of it??
Plz help
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Inertia is what makes heavier objects more difficult to get moving or to stop them from moving. For example, if you push on a bowling ball, it takes more effort to get moving than a soccer ball. Inertia is also the reason a bowling ball is more difficult to stop.
When things are moving in a straight line, inertia is simple. Heavier objects have more inertia.
But what about when things are rotating? That’s when things start to get interesting. The “moment of inertia” is what we use to describe inertia for rotating objects.
If you have an office chair nearby, sit down, extend your arms, and have someone spin you around. Careful, not too fast. Once you’re spinning, quickly pull your arms in, wait a moment, then extend them again.
You’ll notice that you rapidly speed up when you draw your arms in, then slow down when you extend them again. What’s up with that!?
The reason is really interesting, but also very simple. When you spin around with your arms extended, the mass in your hands and arms travels a path that is a circle. The linear distance traveled around one revolution is called the circumference. When you draw your arms inwards, that distance becomes shorter, but the mass in your arms has momentum from traveling a greater distance. By reducing the distance your hands will travel, you speed up your rate of rotation.
So the moment of inertia considers the mass of the rotating object, its angular velocity (same as RPM), and the distance of its mass from the center of rotation. All three of these values are “conserved” under the law of conservation of energy. So if you change any one of those variables, the others will adjust to compensate.
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