Inertia is the property of an object which resists a change in its motion.

If it is at rest it tends to remain at rest , if it is moving it tends to continue moving.

Or

Inertia is the reluctance of an object to move once it is at rest or the reluctance of an object to stop once it is in uniform velocity.

Explanation of inertia by Newton’s First Law of Motion

Newton’s First Law of Motion states that “an object will remain at rest or continue with a constant speed in a straight line unless acted on by an unbalanced force or if the external force acting on the object is zero”

Relationship between mass and inertia

The mass of a body is a measure of its inertia. If a body has a small mass, it will have a small inertia; if its mass is large, then so is its inersia.

Some examples of situations involving inertia

Example 1

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Observation: The coin drops vertically into the glass .

Explaination : The inertia of the coin causes it remain at rest . The coin drops vertically into the glass due its weight.

Example 2

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Obesrvation : The other blocks fall vertically onto the table.

Explaination : The inertia of the wooden blocks causes its remain at rest. The weight of other blocks makes them fall Vertically onto the table.

Example 3

Observation : If some ketchup is stuck in a bottle, it can be dislodged by turning the bottle upside down , thrusting it downwards and stopping suddenly.

Explanation : The inertia of the ketchup causes it maintain its velocity while the bottle is stopped.

Example 4

Observation: When a driver inside a car applies brake Suddenly , the driver and the passengers are surged forwards. Similarly ,when the car accelerates , the occupants will move backwards.

Explanation: The inertia of the driver and passengers cause they maintain their original motion (original