April 24, 2024
Newton’s laws of motion Presentation Physics


Newton’s First Law, also known as the Law of Inertia, is one of the fundamental principles of physics. It lays the foundation for our understanding of motion and how objects behave in the absence of external forces. In this article, we will delve into the details of Newton’s First Law and explore its implications in everyday life.

What is Newton’s First Law?

Newton’s First Law states that an object at rest will stay at rest, and an object in motion will continue to move at a constant velocity, unless acted upon by an external force. In simpler terms, this law tells us that objects tend to resist changes in their motion.

The Concept of Inertia

The key concept underlying Newton’s First Law is inertia. Inertia is the property of an object that determines how it responds to changes in its motion. An object with more inertia will be harder to accelerate or decelerate, while an object with less inertia will be easier to set in motion or bring to a stop.

Examples of Newton’s First Law in Everyday Life

1. Sliding Books

Imagine a book resting on a table. According to Newton’s First Law, the book will remain at rest until an external force, such as a push or a pull, is applied to it. This is why when you slide a book on a table, it eventually comes to a stop – the friction between the book and the table acts as the external force, bringing the book to rest.

2. Seatbelts in Cars

When you suddenly hit the brakes in a car, your body tends to keep moving forward due to inertia. However, the seatbelt prevents you from continuing to move forward by applying an external force. This is an essential safety feature that utilizes the principles of Newton’s First Law to protect you during sudden stops or collisions.

3. Ice Skating

When ice skaters push their feet against the ice, they propel themselves forward. This is because the force exerted by their feet overcomes the inertia of their bodies, causing them to move in the opposite direction. Once in motion, they continue to glide due to the absence of external forces, in accordance with Newton’s First Law.


Newton’s First Law plays a crucial role in understanding the behavior of objects in motion. It explains why objects tend to stay at rest or continue moving in a straight line unless acted upon by an external force. By grasping the concept of inertia, we can appreciate the significance of this law in our everyday lives, from the functioning of seatbelts in cars to the graceful movements of ice skaters.