This law by Newton states that an object will remain at rest, or a moving object will stay in motion in a straight line and with the same speed unless an external and unbalanced force acts on the object.
One application of this Newtonian law is in the launching of projectiles like ballistic missiles. A ballistic missile parabolic path is affected by its inertia and the unbalanced forces acting on the object such as air resistance/ drag and gravity.
