The RHS of the above equation is the integral (over the entire cross-section) of the differential volumetric flow rate:
(Fig. 12d)
Or Ans.
Apply the conservation law again over larger to show that, Ans.
Further, (for the 2nd section) (for the 1st section)
or,
Re-visit,
or, (volumetric flow rate)
or, , average velocity in the section
Compare to to show that .
Ans.
to show that, 
Ans. 
(for the 2nd section) 
(for the 1st section) 
(volumetric flow rate)
, 
average velocity in the section 
. 
