A VENTURI TUBE IS USED TO MEASURE THE WATER SPEED V IN A PIPE BY COMPARING THE WATER PRESSURE IN THE WIDE AND NARROW SECTIONS(CROSS-SECTIONAL AREAS A, A=A/4).FIND V IF THE DIFFERENCE IN MECURY LEVEL IS h=25mm.(THE DENSITY OF MERCURY IS =13600Kg/meter cube)

Answer 1

A2 = A1/4, so you know A1v1 = A2v2
A1v1 = A1/4v2, cancel out the A1's
v1 = 1/4 v2
v2^2 = 16v1^2 --- eqn 1

change in pressure = (rho)gh = 3332 N/m^2
3332 = 1/2(rho)(v2^2 - v1^2)
3332 = (1/2)(1000)(v2^2 - v1^2)
v2^2 = 6.664 + v1^2 --- eqn 2

16v1^2 = 6.664 + v1^2
v1 = 0.6665 m/s

.... I hope this is right.