Solving Fluid Dynamics Pressure at Different Speeds

[narutoish]

Homework Statement

If the pressure reading of your Pitot tube is 17.0 mm Hg at a speed of 150 km/h, what will it be at 700 km/h at the same altitude?

Homework Equations

The only eq I could think if is p = p₂+ 1/2 density (v₂^2 - v₁^2)

But I don't know the density

The Attempt at a Solution

So I pretty much get stuck in the beginning, any help will be nice

Thanks

 

[haruspex]

What would the reading be at 0km/h? What equations do you now have?
(Note: I'm assuming the equation you quoted is appropriate. To check that I'd need to do some research.)

 

[Chestermiller]

Homework Statement

If the pressure reading of your Pitot tube is 17.0 mm Hg at a speed of 150 km/h, what will it be at 700 km/h at the same altitude?

Homework Equations

The only eq I could think if is p = p₂+ 1/2 density (v₂^2 - v₁^2)

But I don't know the density

The Attempt at a Solution

So I pretty much get stuck in the beginning, any help will be nice

Thanks

At the tip of the pitot tube, the velocity is zero. So you are measuring the stagnation pressure. If the density doesn't change between the two cases, how does the stagnation pressure depend on the approach velocity?

Chet