A coffee filter is inserted into a funnel with ridges around the inside. You attempt to remove the filter by blowing through the funnel stem. This approach fails to dislodge the paper mostly likely because (A) you aren't blowing hard enough. (B) in blowing the air you increase the pressure, which by Newton's third law causes the atmosphere to increase the air pressure against the funnel. (C) the blown air lowers the pressure between the filter and funnel walls, allowing the atmospheric pressure to press the filter against the funnel wall. (D) molecular forces cause the filter to stick to the funnel. (E) \((\mathrm{C})\) and (D)

In the context of physics problems involving air pressure, Newton's Third Law is often applied to explore the interaction between forces. It is essential to understand that the Third Law describes action-reaction force pairs. For example, when you push against a wall, the wall pushes back with the same force in the opposite direction. However, the law doesn't directly address changes in air pressure caused by fluid dynamics, which is a common point of confusion.

Considering the exercise problem, the act of blowing air through the funnel doesn't create a force that is directly opposed by atmospheric pressure, as Newton's law would predict with solid objects; hence, we can deduce that the scenario described does not illustrate Newton's Third Law in action. Instead, the blowing action involves pressure differences, leading to the concept of Bernoulli's principle—where fluid dynamics come into play.

Atmospheric pressure is the force per unit area exerted against a surface by the weight of air above that surface in the atmosphere of Earth. At sea level, it averages about 101,325 Pascals or 1 standard atmosphere. This pressure is exerted in all directions, and we are so accustomed to it that we usually don't notice its presence.

However, it becomes apparent in situations where there is a pressure imbalance. In the coffee filter exercise, atmospheric pressure is a crucial component because it is the higher outside pressure that pushes the filter into the funnel when the pressure inside the funnel is reduced by blowing air through it. Understanding atmospheric pressure is vital to grasping how forces in fluids can impact objects in various scenarios, not just in the exercise example.

Bernoulli's principle is quite counterintuitive; it states that within a stream of fluid, there is an inverse relationship between velocity and pressure. As the velocity of a fluid increases, its static pressure decreases and vice versa. This principle is fundamental in explaining how airplanes fly, how chimneys draft air, and even how a coffee filter can stick to the sides of a funnel.

In the given exercise, the principle is the key to understanding why the filter does not dislodge. As air is blown through the funnel, the air velocity between the filter and the funnel increases, which according to Bernoulli's principle, reduces the pressure. This lower pressure means that the greater atmospheric pressure outside the funnel presses the filter against the walls, effectively increasing the friction and preventing it from falling.

Air pressure is a fundamental concept in physics, encompassing the force exerted by the weight of the air molecules in the Earth's atmosphere. It's crucial for a range of phenomena, including weather patterns, breathing, and the working of various machines.

In physics problems, understanding air pressure involves recognizing how it relates to the volume, temperature, and amount of air. The exercise provided showcases the dynamics of air pressure, as the act of blowing into the funnel changes the pressure distribution. By analyzing this, students learn about how changes in air pressure can result in forces that cause physical movement or, as seen with the coffee filter, a lack of movement due to the balance of forces resulting from pressure differentials.