Newton's First Law of Motion, also known as the Law of Inertia, states that an object at rest will remain at rest, and an object in motion will continue moving in a straight line at a constant velocity unless acted upon by an external force.
Inertia is the resistance of an object to changes in its state of motion. It is directly related to an object's mass. Objects with greater mass have greater inertia and require more force to change their motion.
An everyday example of Newton's First Law is when you are in a moving vehicle and it suddenly stops. Your body tends to continue moving forward due to inertia. This is why you may feel the need to brace yourself or hold onto something to prevent being thrown forward.
Another example is when sweeping a floor. If you push a broom and suddenly stop, the dust particles tend to keep moving forward due to their inertia.
Understanding Newton's First Law of Motion is fundamental as it provides the basis for understanding the behavior of objects in the absence of external forces. It helps explain why objects maintain their state of motion and how external forces can alter that motion.