Newtons First Law

Newtons First Law

In the area of Physics called Classical Mechanics, Newton’s three laws of motion are Foundational Concepts. Newton, in 1686, presented his three laws of motion in the book Principia Mathematica Philosophiae Naturalis.

  • The First Law states In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity unless acted upon by an external force.
  • This law is also known as the law of Inertia.
  • The basic idea is that a body, if at rest cannot move or if in motion doesn’t stop or accelerate unless another force is acting on it.

Newton’s First Law can be best visualized in a space scenario. Imagine a spaceship floating in space with a constant velocity. It can only stop if it hits an object or pushes itself in the opposite direction. Otherwise, it continues to move. Similarly, in order for it accelerates, it must boost itself. Otherwise, it will move at a constant speed. This is the crux of Newton’s first law of motion. This phenomenon or tendency of an object to stay in its state is known as Inertia.

“The tendency of the body to stay at rest if it is at rest or to stay in motion if it is in motion is known as inertia. Inertia is a key concept in physics and comes in many places including rotational motion.”

Although it might seem like a Simple Idea, Newton’s laws of motion are the key to classical mechanics. Even today, classical mechanics is applied very often. With the theory of relativity, many assumptions we had about the working of the universe have changed. Classical mechanics is by no means perfect, but it is a very good approximation. With it, we have built rockets and have traveled to the moon. Newton’s laws are very crucial at the micro-level too.

Any undergrad physics course will have a lesson on classical mechanics and Newton’s laws of motion. Going in deeper, the first law implies that in order for there to be motion or lack thereof, there needn’t be any force. So, a system will be perfectly balanced if no force is applied if it is already balanced. But the question to be asked is about the systems which are unbalanced by nature. In such systems, the first law of motion becomes crucial to solving many problems and producing a balanced system.

Newton’s First law is used for a lot of real-life applications. The obvious one is in crash testing of cars. When a car hits something while moving, in order to keep the passengers safe, cars have a lot of safety instilled in their design such as airbags. In order to be safe, one must estimate the amount of force that would be possibly affecting the car during a crash. Once this is found out, it then becomes easy to find ways to ensure safety. Here too, the first law of motion comes in handy. Even in the launch of rockets, while in motion, masses are dropped off of the rocket in order to boost their speed. So, Newton’s first law of motion is a fundamental principle of classical physics and is still widely used to solve many problems and asses a lot of physical systems.

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