Which equation represents Newton's Second Law?

Which equation represents Newton's Second Law?

• A. The rate of change of velocity.
• B. The sum of forces equals zero in equilibrium.
• C. F = m × a.
• D. Energy equals work done.

Answer: (C)

Newton's Second Law links the cause of motion to how that motion changes. It says the net external force acting on a body equals its mass times its acceleration. This means the acceleration a body experiences is determined by both how strong the force is and how heavy the body is: heavier objects need more force to achieve the same acceleration. Acceleration is the rate at which velocity changes, and the law uses the net force (the vector sum of all forces) to produce that change. In equilibrium, the net force is zero, which means no acceleration occurs—this is a special case of the same law, not the general statement. The idea that energy equals work done describes a different relationship—the work-energy connection—not the direct link between force and acceleration. So the equation that embodies Newton's Second Law is F = m × a.

Newton's Second Law links the cause of motion to how that motion changes. It says the net external force acting on a body equals its mass times its acceleration. This means the acceleration a body experiences is determined by both how strong the force is and how heavy the body is: heavier objects need more force to achieve the same acceleration. Acceleration is the rate at which velocity changes, and the law uses the net force (the vector sum of all forces) to produce that change.

In equilibrium, the net force is zero, which means no acceleration occurs—this is a special case of the same law, not the general statement. The idea that energy equals work done describes a different relationship—the work-energy connection—not the direct link between force and acceleration. So the equation that embodies Newton's Second Law is F = m × a.