What does newton’s first law of motion state? 1st law

In physics, the laws of motion are the very basic laws of classical mechanics part. Sir Isaac Newton gave three laws of motion. In this article, we are going to discuss Newton’s first law of motion, what does newton’s first law of motion state? Explanation of Newton’s 1st law of motion with examples.

Contents in this article:

  1. Statement of Newton’s first law of motion
  2. Explanation of Newton’s first law of motion
  3. Examples of Newton’s first law of Motion
  4. Significance of Newton’s first law of motion
  5. Inertia

What does newton’s first law of motion state?

Newton’s first law of motion states that if no external force is applied on a body, then if the body is at rest it will remain at rest forever and if the body is in motion then it will be moving in straight line with the same velocity forever. This is the statement of Newton’s 1st law of motion.

Explanation of Newton’s first law

Newton’s first law of motion describes two cases.

  1. Suppose you have placed an object on a table or on the floor. Now, if no external force is applied on the body it will remain there at rest forever. But if we apply a sufficient force on it, the according to the Newton’s first law of motion the object at rest will begin to move.
  2. In the second case, let the same object is now moving as we have applied an external force and released it. Now the force is not acting, but the object is moving due to that initial force. Here, Newton’s 1st law says that this moving object will be moving with the same velocity along the same straight path forever. Its velocity will neither increase nor decrease until an external force is applied.

Now, you may say that when ever we through an object along the floor it stops after some distance. So, this is violating Newton’s first law of motion. But this is not true. Because, according to Newton’s law, that object will be in motion with same velocity and direction if no external force acts on it. But here the air resistance and the friction force between the object and the floor are acting on this object. These forces are opposing its motion and that is why it stops after some distance.

Examples of Newton’s first law of motion

There are so many examples for Newton’s first law of motion. Here I am mentioning only three of those.

  1. When a bus suddenly starts to accelerate passengers fall backwards. This is because the passengers were initially at rest and still trying to be at rest. But the bus started to move suddenly.
  2. When a moving bus stops suddenly, passengers fall forward. This is just opposite thing of first example. In this case passengers were initially in motion and still trying to be in motion. But the bus stops suddenly.
  3. The fan continues to rotate for a few time even after the switch is turned off. This is because the fan was initially in motion and still trying to be in motion. But it stops after some rotations because of the air resistance and the friction force of the joints of the fan system.

Significance of Newton’s first law of motion

There are two major significance of Newton’s first law of motion. These are –

  1. Newton’s first law of motion gives the idea of inertia of a body. This is why the Newton’s first law of motion is also called the law of inertia.
  2. From the fist law of motion we get the definition of force.

Inertia

Inertia is a property of matter by which it can stay at its existing state of rest or uniform motion along a straight line in absence of net external force. So, the inertia is nothing but the tendency of staying in its current state of motion or rest. There are two types of inertia –

  1. Inertia of rest
  2. Inertia of motion

We are going to discuss these one by one at below.

Inertia of rest

The inertia of rest of an object is the tendency of staying at its existing state of rest. That means if a body is at rest, it will try to be at rest. This state is the inertia of rest.

Example: when a bus suddenly starts to accelerate passengers fall backwards. This is because the passengers were initially at rest and still trying to be at rest.

Inertia of motion

This is just opposite to the inertia of rest. Inertia of motion is the tendency of the object of staying at its existing state of uniform motion in a straight line. This means that a moving body will not change its velocity and direction due to its inertia of motion.

Example: A fan continues to rotate for a few times even after turning off the switch. Another example of inertia of rest is when a moving bus stops suddenly, passengers fall forwards.

People also ask:

  1. What does Newton’s first law of motion describe?
  2. Explain Newton’s first law of motion in your own words.
  3. What does Newton’s first law of motion tell us?
  4. Definition of Newton’s first law of motion.
  5. What does Newton’s first law of motion cover?
  6. Equation for Newton’s first law of motion.
  7. Examples of Newton’s first law of motion in daily life.

So, this is what Newton’s first law of motion state. If you have any doubt on this topic you can ask me in the comment section.

Thank you!

Related posts:

  1. Newton’s second law of motion
  2. Newton’s third law of motion with example
  3. Fourth law of motion by Newton

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