# Low pressures at high velocities

• Jewish_Vulcan
In summary, the pressure decreases as the velocity increases due to the Bernoulli's effect or principle, which is based on the conservation of energy. This is because as the speed of the fluid increases, the particles hit the edge of the medium less, requiring less pressure to accelerate the fluid. This is explained by Newton's Second Law, F = ma, where a higher pressure is needed upstream to accelerate the fluid.

#### Jewish_Vulcan

Why does pressure decrease as velocity increases, I think it is because pressure is defined as particles hitting the edge of the medium so when velocity increases the particles hit the edge of the medium less but how?

It is called the Bernoulli's effect or principle and is to do with the conservation of energy. If speed increases then pressure has to decrease so the total energy remains the same.

Jewish_Vulcan said:
Why does pressure decrease as velocity increases, I think it is because pressure is defined as particles hitting the edge of the medium so when velocity increases the particles hit the edge of the medium less but how?
This is an F = ma (Newton's Second Law) kind of thing. If the velocity is increasing, then the fluid is being accelerated. In order to accelerate the fluid, you need to apply a higher pressure (force per unit area) upstream than downstream.

Chet

Jewish_Vulcan
Chestermiller said:
This is an F = ma (Newton's Second Law) kind of thing. If the velocity is increasing, then the fluid is being accelerated. In order to accelerate the fluid, you need to apply a higher pressure (force per unit area) upstream than downstream.

Chet
ok thank you, I was thinking that but could not really visualize it, I guess sometimes you just have to trust equations even if they do not make sense...