A U$-$tube open at both ends is partially filled with water $($Figure $($a$)).$ Oil $(0=750k\frac{g}{m^3})$ is then poured into the fight arm and forms a column $L=6\mathrm{.}54cm$ high $($Figure $($b$)).$

$(4)$

$($a$)$ Determine the difference $h$ in the heights of the two liquid surfaces. $($The density of water is $1\mathrm{.}00{10}^{3}k\frac{g}{m^3}.)$ cm

$($b$)$ The right arm is then shielded from any air motion while air is blown across the top of the left arm until the surfaces of the two liquids are at the same height $($Figure $($c$)).$ Determine the speed of the air being blown across the left arm. Assume the density of air is $1\mathrm{.}29k\frac{g}{m^3}.$

$\frac{m}{s}$