When blood pressure is measured, why must the jacket be held at the level of the heart?
I don't quite understand the answer given.
The Attempt at a Solution
It's obvious that if the the height changes the pressure reading will change due to P=ρgΔh, thus giving a 'false' reading when it's blood pressure from the heart that we are wanting to know.
I thought that if the jacket if lower than the heart, then the pressure reading will be lower.
And if the jacket if higher than the heart, then the pressure reading will be higher
Just taking some random numbers here for an example,
P= (1.05x10^3) x 9.8 x 2
P= 20580 Pascals compared to...
P= (1.05x10^3) x 9.8 x 3
P= 30870 Pascals
However the answer in book says that if the jacket is lower, then blood pressure will be higher and vice versa without giving an explanation and I can't work out why this is. It doesn't seem logical to me. Can someone please explain?