Question

Which has more inertia: a $1$ kilogram ball or a $10$ kilogram ball?

Answer 1

Newton formulated three laws which almost governs whole classical mechanics Kinematics. In this the first law of motion which is also sometimes called the law of inertia.

Complete step by step answer:
It states that if no external force is applied on the body, then a moving body will continue to move with same velocity forever as well as a body at rest will remain at rest forever, this property is called inertia of rest and inertia of motion.
Now, according to the question we have two balls having mass of $1kg$ and $10kg$ so, in order to change their state of inertia we have to apply some force, so force on a body is directly proportional to mass of the body which means larger the mass of a body greater the force required to move, so a larger force required to change inertia of a body implies that it has greater inertia.
So, we conclude that the larger the mass of a body the larger its inertia.
Hence, a ball of mass $10kg$ will have more inertia.

Note: It should be remembered that, the force required to change the state of inertia of any body is given by Newton's second law of motion in which applied force is simply the product of mass and acceleration produced on the body. Inertia is a qualitative property of a body.