What does Newton's first law of motion describe?

What does Newton's first law of motion describe?

• A. Objects in motion slow down
• B. An object at rest stays at rest; an object in motion remains in motion unless acted upon
• C. All objects fall at the same rate
• D. Force is proportional to mass and acceleration

Answer: (B)

Newton's first law of motion describes the concept of inertia, which states that an object at rest will remain at rest, and an object in motion will continue to move in a straight line at a constant speed unless acted upon by a net external force. This principle underscores the idea that a change in the state of motion of an object—whether it is starting to move, stopping, or changing direction—requires the intervention of an external force. This law emphasizes the natural tendency of objects to resist changes to their state of motion, highlighting the concept of inertia. For instance, if you slide a book across a table, it eventually slows down and stops due to the frictional force acting against it. In the absence of such forces, the book would keep sliding indefinitely. Thus, the correct answer encapsulates the essence of inertia as detailed in Newton's first law.

Newton's first law of motion describes the concept of inertia, which states that an object at rest will remain at rest, and an object in motion will continue to move in a straight line at a constant speed unless acted upon by a net external force. This principle underscores the idea that a change in the state of motion of an object—whether it is starting to move, stopping, or changing direction—requires the intervention of an external force.

This law emphasizes the natural tendency of objects to resist changes to their state of motion, highlighting the concept of inertia. For instance, if you slide a book across a table, it eventually slows down and stops due to the frictional force acting against it. In the absence of such forces, the book would keep sliding indefinitely. Thus, the correct answer encapsulates the essence of inertia as detailed in Newton's first law.