chaitnyakishore
Last Activity: 10 Years ago
Let us consider a tube AB of varing cross-section with water is flowing through that tube.
At side A, area of cross-section be A1
velocity of fluid be v1
At side B, area of cross-section be A2
velocity of fluid be v2
and density of water be d and let A1>A2
Now v=distance travelled/time=l/t --->l=vt
---> Mass of fluid entered the tube at A in tseconds, m1=dV1=dAl=dA1v1t ----->(1)
---> Mass of fluid leaved the tube at B in tseconds, m2=dV2=dAl=dA2v2t ----->(2)
But mass of fluid which entered into the tube is equal to the mass of fluid leaved the fluid.
Therefore from equations (1) and (2)
m1=m2
dA1v1t=dA2v2t
Therefore A1v1t=A2v2t
Therefore Av=constant