# What is Newton’s First Law of Motion ?

A body remains in the state of rest or uniform motion in a straight line unless and until an external force acts on it.

According to Newton’s first law of motion, a body won’t begin to move unless and until an outside force acts on it. When something starts moving, it won’t stop or change its speed unless another force acts on it. The law of inertia is another name for the first law of motion.

The first law of motion is dependent on two circumstances:

i) Objects at rest: The velocity (v) and acceleration (a) of an object are both zero when it is at rest. The object remains at rest as a result.
ii) Objects in motion: When an object is moving, its acceleration (a = 0) and velocity (v) are both equal to zero. As a result, the object will continue.

The First Law of Motion by an Example

Take a block and place it on a flat surface. When we say a surface is smooth, we mean there is no friction present. The block is not moving because it is at rest.

Let’s now investigate the forces affecting the block. The only forces acting on the block are gravity and the surface’s usual reaction. It is not being affected by any horizontal force. There is no external force acting on the block because the forces acting in the vertical direction are equal in magnitude to one another. We can say that this block confirms Newton’s first law of motion because it is at rest.

The block will now begin to move with some constant acceleration in the direction of the applied force if we apply a constant force F to it in a horizontal direction.

Examples of Newton’s First Law of Motion in Daily Life

Using a seat belt while driving a car is an illustration of Newton’s first law of motion. The body will tend to continue moving forward due to inertia in the event of an accident or abruptly applying the brakes to the vehicle, which will likely be fatal. Seat belts are used to stop your body from moving forward inertia and avoiding danger in order to prevent such accidents.