- #36

songoku

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The given answer is 600 seconds. So I guess my working and equation is already correct so it is just a matter of plugging valueharuspex said:I got 64,000s before, much closer to the given answer. I'll try to find my scribbles.

The time I need to calculate is only the time taken to reach the apex of the pipe? No need to calculate the time taken by the water to fall from apex to the container and add them to get total time?

The constant force comes from: ##F=P_{\text{atm}} \times \text{area of pipe}## ?At any instant the whole column will move at the same speed, but it has diminishing mass and a constant force, so not only will the speed increase, the acceleration will increase.

If, let say, I want to continue to the vertical pipe on the container's side, is this how I do it:

##F=P.a##

##\frac{d(mv)}{dt}=P.a##

##v.\frac{dm}{dt}=P.a##

##v.\frac{d(\rho V)}{dt}=P.a##

##v.\rho \frac{d(a.H)}{dt}=P.a##

##v.\rho .a \frac{dH}{dt}=P.a##

##v.\rho \frac{dH}{dt}=P##

Then integrating to get ##H## in term of ##t##, find the constant of integration by putting ##H=20~m## for ##t=0## and finally find the time taken by all water to go in container by setting ##H=0##?

Thanks