How do airplanes use density?
WIthout further clarification there are a couple possible answers: a) Airplanes balance their load by balancing the amount of fuel in the tanks in each of the wings. As one tank empties the plane becomes unbalanced, so fuel from the other wing is transferred into it to balance the load. b) The shape of the wing disturbs the air above it, causing it to move faster over the top of the wing than underneath the wing: To understand flight, it’s necessary to grasp the physical laws that govern airflow. Just as solid bodies obey Newton’s laws of motion (that describe inertia, the relationship among applied force, mass and acceleration, and equal and opposite reaction), so do fluids such as air. To change the velocity or the direction of airflow, a force must be applied to the air in the form of a pressure difference. When there is a pressure difference, air tends to flow from the high pressure to the low pressure region. Therefore, as air speeds up, pressure decreases, and vice-versa (this is
