Physics: Newton's Laws of Motion

Law 1: The first law of motion is the definition of inertia. For example, an object at rest has no net force because all external forces are canceling out, therefore the object is maintaining a constant velocity. In this case, the object has zero velocity. If an external force applied in increased then the object's velocity will change.

Law 2: This law explains how the velocity of an object changes when an external force is applied. This law defines that force is equal to change in momentum per change in time.

Law 3: The third law states that for every action, there is an equal and opposite reaction. For example, if object A exerts a force on object B, then object B will exert an equal force on object A. A modern example would be rowing a boat.