What is inertia

Inertia is a fundamental concept in physics, describing an object’s resistance to changes in its motion. Specifically:

1. Definition: Inertia is the property of an object that resists changes to its state of motion or rest.
   • If an object is at rest, it tends to stay at rest.
   • If an object is moving, it tends to keep moving in a straight line at a constant speed unless acted upon by an external force.
2. Relation to Mass: The amount of inertia an object has is directly proportional to its mass. A heavier object (with more mass) has greater inertia and requires more force to change its motion compared to a lighter object.
3. Newton’s First Law: This property is encapsulated in Newton’s First Law of Motion, also called the Law of Inertia. It states: “An object at rest will stay at rest, and an object in motion will stay in motion at a constant velocity, unless acted upon by an unbalanced force.”
4. Everyday Examples:
   • When you suddenly brake in a car, your body tends to lurch forward because it resists the change in motion.
   • A heavy truck is harder to start moving or stop than a small car due to its greater inertia.

In summary, inertia is an intrinsic property of matter that reflects its tendency to maintain its current state of motion unless a force intervenes.