State and explain the law of inertia (or Newton's first law of motion).

(N/A) Newton's first law of motion,also known as the law of inertia,states that an object will remain at rest or continue to move at a constant velocity in a straight line unless acted upon by an external unbalanced force.
This law implies that objects have a natural tendency to resist changes in their state of motion,a property known as inertia.
For example,a book lying on a table will remain there until someone pushes it,and a ball rolling on a frictionless surface would theoretically continue moving forever unless stopped by an external force.