Consider a tube having variable cross section and is placed vertically. The upper part it has a cross section of $4\ \mathrm{mm^2}$ and the lower part has a cross section of $2\ \mathrm{mm^2}$.
If water enters per second through upper part (say at a rate of $V\ \mathrm{cm^3}$) will equation of continuity be valid to calculate velocity at the lower part. (I don't think so because gravity will accelerate the fluid).
And if it is valid then does it means that no matter in what orientation the tube is placed ( whether horizontal or vertical) velocity at smaller cross section will be the same?
Here with equation of continuity I specifically mean this equation $A_1v_1=A_2v_2$. Will this be valid in both the cases.
Consider this figure for reference
Best Answer
Pascals law does not apply here. It is only true for static situations.