why do heavier objects have more inertia
Confidence votes 317. Inertia is rotary momentum; an object's ability to continue spinning when a decelerating force is applied. Just as a heavy object takes more effort to stop from the same speed as a light object, so does a heavy object take more effort to stop from turning at the same speed as a light object. So assuming they are turning at the same angular velocity, the heavier one has a larger inertia.