In classical mechanics, the study of motion and forces, it is often convenient to ignore the effects of air resistance or drag. This simplification is made for several reasons:
Complexity reduction: Accounting for air resistance significantly complicates the mathematical equations involved in describing the motion of objects. It involves considering fluid dynamics, which introduces additional variables and equations that can make the problem much more challenging to solve.
Limited applicability: Air resistance becomes significant only at higher speeds or in the presence of a large surface area. For many everyday objects and situations, the effects of air resistance are relatively small and can be neglected without significantly affecting the accuracy of the analysis.
Idealized scenarios: Classical mechanics often deals with idealized scenarios to understand fundamental principles and make predictions. By ignoring air resistance, we can focus on the basic concepts of forces, motion, and energy conservation without the added complexity of fluid dynamics.
Teaching and learning purposes: Ignoring air resistance in introductory physics courses allows students to grasp the fundamental principles of classical mechanics without getting overwhelmed by the intricacies of fluid dynamics. It provides a simpler starting point for building a foundation of understanding.
It's important to note that while air resistance is neglected in classical mechanics, it becomes increasingly significant as speeds or sizes increase. For objects moving at high speeds or in situations where air resistance plays a crucial role, more advanced theories such as fluid dynamics or computational fluid dynamics are employed to accurately describe the motion.