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Which principle describes that a body at rest will remain at rest unless acted upon by an external force?
Newton's First Law of Motion
Newton's Second Law of Motion
Newton's Third Law of Motion
The Law of Universal Gravitation
The correct answer is: Newton's First Law of Motion
The principle that a body at rest will remain at rest unless acted upon by an external force is encapsulated in Newton's First Law of Motion. This law, often referred to as the law of inertia, highlights the tendency of objects to maintain their state of motion. Essentially, if no net force acts on an object, it will not change its state—meaning a stationary object will remain stationary, and an object in motion will continue to move in a straight line at a constant speed. Understanding this law is fundamental in various fields, particularly in physics and engineering, as it lays the groundwork for understanding how forces affect motion. For example, if a moving car suddenly hits a barrier, the occupants inside feel a jolt backward, illustrating the principle of inertia, where the body continues in motion while the car stops due to the impact. Newton's Second Law of Motion discusses how the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This is not applicable when describing a body at rest. Newton's Third Law of Motion addresses the action-reaction principle, stating that for every action, there is an equal and opposite reaction. The Law of Universal Gravitation describes the attractive force between two masses and