What is Inertia?
Inertia is the natural tendency of an object to resist a change in its state of rest or state of motion.
In simpler terms, objects tend to keep on doing what they are doing. If they are at rest, they continue being in rest and if they are in motion with a constant velocity, they continue moving with the same velocity in the same direction.
Inertia tells us how strong an object’s tendency is to resist change in its state of motion.
What is the Law of inertia?
The Law of inertia is nothing but Newton’s first law of motion, that is – An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an external force or an unbalanced force.
What is the relation between Inertia and Mass?
The inertia of a body depends on only one factor – the mass of that body.
Greater the mass of a body, greater is its ability to resist the change in its state of rest or motion. Hence, we can say that the mass of an object is the measure of its inertia.
Example of inertia
Consider two bricks of different masses. When the bricks are pushed from their original state of rest, the heavier brick will be tougher to push, as compared to the lighter one. This means the heavier brick offers greater resistance to change its position.
From this we can conclude that the brick with a greater mass has a greater tendency to resist change in its state of rest; hence it has greater inertia as compared to the lighter brick.