The First Law of Motion - Newton's First Law of Motion


A typical answer to this one is "An object at rest or in constant motion tends to remain in that state unless an outside force acts to change such state". 
Simple and easy to recall but the generalized statement reduces the concept associated with such a statement. When I lecture about this Law, the divide it into two with the second statement further subdivided to two.

Newton's First Law of Motion

1. An object at rest tends to remain at rest unless a net force acts to make it move.

• An object in constant velocity will remain in such state of motion unless a net force acts to change that constant velocity.
• An object in constant angular velocity will remain in such state unless a net torque acts to change the constant angular velocity.