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Old 12th January 2006 | 00:12
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Capt Pit Bull
 
Joined: Aug 1999
Posts: 1,050
Likes: 4
From: England
Re: Help on Dynamic pressure formula

Look at the dimensions of Density and Velocity.

(sorry no superscript)

rho = Kg.M-3

V = M.S-1

V2 = M2.S-2

so dynamic pressure units can be stated as

Kg.M-3.M2.S-2

Simplifies to

Kg.M-1.S-2

We are looking to equate the dimensions to Pa, = N.M-2

Can we rearrange the units to make it fit? Use Newtons second law.

F = MA

or better, M = F / A

so Kg = N / (M.S-2)

so Kg = N.M-1.S2

Substitute for mass units in our earlier formula Kg.M-1.S-2

yields N.M-1.S2.M-1.S-2

Seconds cancel out, leaves dymnamic pressure units:

N.M-1.M-1 i.e. N/M2

Hope thats what you wanted. I think its right, though its late.

(c) PB
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