Why can Newton’s laws accurately describe bridges, aircraft, and many ordinary objects?

Newton’s laws of motion accurately describe ordinary objects, such as bridges and aircraft, because they serve as an effective approximation of physical reality for bodies that are relatively large and moving at speeds much lower than the speed of light.12

While quantum mechanics and relativity are considered more fundamental in modern physics, these theories reduce to Newton’s laws when applied to macroscopic objects. Engineers rely on these laws with confidence because they provide the necessary precision to calculate forces, equilibrium, and motion in complex systems. For instance, statics—a branch of mechanics derived from these laws—is essential for ensuring the stability of structures like bridges by accounting for forces such as gravity, tension, and compression. Similarly, the principles of aerodynamics utilize these classical foundations to analyze the forces acting on aircraft and other vehicles.12345

Ultimately, Newton’s laws remain a powerful and reliable tool for understanding the physical world in everyday contexts.2