Force and Laws of Motion

First Law of Motion

Statement

An object remains at rest or in uniform motion unless acted upon by a net external force.

Inertia

The tendency of an object to resist changes in its state of motion, the state of rest or the state of motion. Higher the inertia, more will be the resistance.

First law of motion is, hence, also called as Law of Inertia.

Types of Inertia

1. Inertia of Rest: The tendency of an object to remain in the state of rest unless acted upon by an external force.
2. Inertia of Motion: The tendency of an object to move continuously at a constant velocity unless acted upon by an external force.
3. Inertia of Direction: The tendency of an object to move in same direction unless acted upon by an external force.

Factors Affecting Inertia

1. Mass: Higher the mass of an object, the greater is its inertia. Mass is a measure of an object’s inertia.
2. Distribution of Mass: Important for resistance against rotational motion.