A manometer containing mercury is connected to two points A and B 15 m apart, on an inclined pipeline conveying water as shown.?

The pipeline is straight and slopes at an angle of 15 o with the horizontal. The manometer gives a reading of 150 mm. Calculate the pressure difference between the two points A and B. (Specific weight of water = 9.81 kN and S.G of Hg= 13.6)enter image source here

1 Answer
Mar 20, 2018

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If pressure at point AA is PP and at BB is P',then considering pressure at a horizontal level passing through s we can write,

P+(pq+qr+rs) rho*g=P' + qr*rho* g + rs *13.6*1000*g (1 g/(cm^3) = 1000 (Kg)/m^3)

where, rho*g=9.8kN

Now,from the diagram pq=15 sin 15=3.87m

given, rs=150/1000 m

So,putting the values we get,

P + 3.87*rho*g +qr*rho*g +rs*rho*g = P' +qr*rho*g +19992

or,P +3.87*9.8*10^3 +(150/1000)*9.8*10^3=P'+19992

or, P-P'=19992-39396=-19404 Pa