Perfect Gas Law
The perfect gas law establishes the relationship between the pressure, density, and temperature of a gas at any instant in time or space. Air is treated as a perfect gas, even though it is a mixture of gases; it is mostly nitrogen. Engineers regularly use the perfect gas law to compute air flow properties.
Bernoulli's Theorem
Daniel Bernoulli (1700 -1782) discovered how velocity and pressure change in a fluid: when the velocity in the flow increases, the pressure decreases, and when the velocity decreases, the pressure increases. This theory was vital in designing wings to make flight possible.
Newton's Laws
Among many contributions, Sir Isaac Newton developed three laws of physics. These laws help explain air and space flight. Newton's first law states that a body will remain at rest until acted on by a force. Newton's second law defines what a force is. A force is equal to mass times acceleration or F=ma. Newton's third law states that for every action there is an equal and opposite reaction. Let's look at how Bernoulli's theorem and Newton's laws help explain how aircraft and tennis balls fly.