- #1

- 9

- 0

## Homework Statement

Calculate the difference in pressure (in atmospheres) that the blood vessels in a giraffe's head have to accommodate as the head is lowered from a full upright position to ground level for a drink. The height of an average giraffe is about 6m.

(Note I'm currently only looking for the answer is Pascals)

## Homework Equations

I thought the equation was P=Po + pgh

but the answer just says P=pgh

Po= 101000Pa

## The Attempt at a Solution

P=Po + pgh

P=101000 + (1.05x10^3 kg/m^3) x 9.8 x 6m

P=162.740Pa

But the answer gives...

ΔP=pgΔh

[itex]\frac{ΔP}{Po}[/itex] = [itex]\frac{pgΔh}{Po}[/itex]

= [itex]\frac{(1.05\times10

^{3})\times9.8\times6}{1.013\times10

^{5}}[/itex]

=0.609Pa

I don't understand why they've rearranged the equation the way they have and exactly how they are using it. It just doesn't seem right.

Can someone please explain?