Initial speed v = 15 cm / s = 0.15 m / s
speed after v ' = 30 cm / s = 0.30 m / s
Pressure drop = ( 1/ 2) Ï[ v ' ^ 2- v ^ 2]
                      =
0.5 * 1.225 * [ 0.0675 ]
                   Â
= 0.043 Pa
(or)
By Bernoullis principle:
    Δp  = (1/2)density
(v22 - v12
)Â Â Â
           Â
= (1/2)density (2v12 -
v12 )Â Â
            Â
= (3/2)density ( v12 )
so:  Δp  = (3/2) * 1.29kg/m3 *
(0.17 2 )
            Â
= 0.0559 Pa
                      =
33.75 Pa
