fluid mechanics :fluid in motion

gikwiye

1. The problem statement, all variables and given/known data
a vertical, 1cm-diameter jet of water impinges upon a bathroom scale such that the latter exhibits a reading of 5 kg. Estimate the volume flow rate of the jet.

2. Relevant equations
p=F/A
Q(volume flow rate)=U*A(area where the jet of water is applied on)
a=pi*r²
F=mg
P=(rho*U²)/2 (if we consider that the pressure applied on the scale by the jet is essentially dynamic pressure) (don't know if this is correct though)


3. The attempt at a solution
let's calculate A first
A=2.5x10^(-5)*pi
then let's change the kg into Newtons:
F=5*9.81=49.05N
P is F/A therefore: P=49.05/(2.5*10^(-5))=624.523kpa
with P=(rho*U²)/2 if find U=35.341m/s
and with
Q(volume flow rate)=U*A(area where the jet of water is applied on)
I find Q=2.7756 l/s
just wanna know if I should include the atmospheric pressure or not

gikwiye

found it