Question

state Newton's first la2 of motion.why is it known as the law of inertia.

Answer 1

NEWTON's First law of motion: Every object in this universe would be in rest or in uniform motion in a straight line if its in rest or motion respectively until
 unless expelled by an external force.
It is also known as inertia because it occurs naturally and inertia is the tendency of an object to resist its change in state of motion or rest.

Answer 2

Newton's first law of motion states that:
     An object remains in the state of rest or of uniform motion in a straight line unless compelled to change that state by an applied force.
     All objects resist a change in their state of motion.In a qualitative way, the tendency of undisturbed objects to stay at rest or keep moving with the same velocity is called inertia.
     That is why the first law of motion is also known as law of inertia.