Answer
$50.0lb$
Work Step by Step
We can determine the required force as follows:
We know that:
$\frac{dm}{dt}=\rho Q$
$\implies \frac{dm}{dt}=(1040)(0.04)=41.6=Kg/s$
The velocity of the jet can be calculated as
$v_a=\frac{Q}{A}$
$\implies v_a=\frac{0.04}{(0.051)^2)(3.14)}=4.90m/s$
Now, $F=\frac{dm}{dt}[(v_b)_y-(-v_a)_y]$
We plug in the known values to obtain:
$F_y=41.6(0+4.9)$
$F=203.64N=50.0lb$
