What is Bernoulli's Principle and Pascal's Principle?

The Bernouli Principle states that sideward pressure exerted by a moving fluid decreases as the fluid's velocity increases.

Any change in the pressure applied to a completely enclosed fluid is transmitted undiminished to all parts of the fluid and the enclosing walls.

Bernoulli's principle is that when the velocity of a fluid (air) increases, its pressure decreases.

In simple terms, if a fluid is flowing through a pipe, as the radius of the pipe decreases the speed of fluid flow must increase and visa-versa.

because it helps design plains and helicopters