An object at rest remains at rest, and an object in uniform motion continues in that state of motion unless acted upon by an external unbalanced force. This statement corresponds to which law of motion formulated by Newton?

Introduction / Context:
Newton laws of motion form the foundation of classical mechanics and describe how forces affect the motion of bodies. The statement given in the question is the famous law of inertia, often encountered early in physics courses. The question tests whether you can correctly associate this verbal description with the appropriate numbered law among Newton three laws of motion.

Given Data / Assumptions:
- An object at rest tends to remain at rest.- An object in uniform motion in a straight line continues that motion.- Any change in this state requires an external unbalanced force.- The statement is one of Newton laws of motion.

Concept / Approach:
Newton first law of motion is called the law of inertia. It states that if the net external force on a body is zero, the body remains at rest or moves with constant velocity in a straight line. This law formalises the idea that motion or rest alone does not require a cause but a change in motion does. Newton second law relates net force to the rate of change of momentum, and Newton third law explains the mutual nature of forces between interacting bodies. There is no fourth law in the standard set of Newton laws.

Step-by-Step Solution:
1. Recognise the law of inertia from the phrase an object at rest remains at rest and an object in motion continues in motion.2. Recall that Newton first law specifically states this principle and introduces the concept of inertial frames.3. Remember that Newton second law deals with F = m * a and rate of change of momentum.4. Recall that Newton third law uses the phrase for every action there is an equal and opposite reaction.5. Note that there is no accepted Newton fourth law in the basic set taught in physics.6. Therefore, match the given statement with Newton first law of motion.

Verification / Alternative check:
Any introductory physics textbook labels the law of inertia as Newton first law and quotes a version very similar to the statement in the question. Classroom demonstrations, such as the tablecloth trick or inertia of a coin on a card, are always linked with the first law. These consistent associations across many learning resources confirm that the correct answer is Newton first law of motion.

Why Other Options Are Wrong:
- Second law of motion: This law relates net force to acceleration and does not state that bodies remain in uniform motion when net force is zero.- Third law of motion: This law describes action and reaction forces, not the persistence of motion or rest.- Fourth law of motion: There is no recognised fourth law in Newton standard formulation.

Common Pitfalls:
Students sometimes confuse the numbering of Newton laws, especially between the first and second. A helpful memory aid is that the first law deals with inertia and describes what happens when net force is zero, while the second law quantifies what happens when net force is non zero. Keeping this distinction clear will help you answer similar questions quickly in examinations.

Final Answer:
The statement describes Newton first law of motion, also known as the law of inertia.