Example Problems with Bernoulli's equation #1

[@reubenschmidt1470]

I guess another way to interpret Av=V/t is through units: m^2 x m/s = m^3 / s. This helped me to understand that jump better.

[@LOVEAD2]

4:32 for b we could have just gone with a2v2= Q right?

[@MrBdubsSAS]

Yes, correct! As long as you convert it to the proper units. You need to use m^3/s not L/s.

[@joffersonfuraque8221]

why was the diameter of the point one (0.08) not added in the total height of the point 2?

[@MrBdubsSAS]

The ambient pressure at the top of the tank and the ambient pressure as the fluid leaves the tank is the same, as both are open to the outside! There is a negligible difference in air pressure at those two points.

[@starla0005]

Hi can you help me into this problem. The flow of water from a reservoir passes through a 12 m long spillway. It takes 30 minutes to lower the water surface from elevation 82 m to elevation 81 m with the crest elevation at 80 m. What would be the final elevation of water surface after 18 minutes?

[@MrBdubsSAS]

The problem gives that the radius of the pipe at point 1 is 16 cm. Therefore, to find the velocity at point 1, you need to use the radius at that point (0.16 cm). :)

[@MrBdubsSAS]

Good question, but, no. As we want something under a certain height of fluid (y) to experience a positive pressure, a positive height of fluid would then require a positive g. I suppose that under some conventions, you could treat that as a negative depth, as it is under the fluid, in which case you would consider down to be negative, and therefore g, being down, could also be treated as negative. This, again would result in a total positive pressure.

[@OboeFiles]

I wish the video and sound quality was better....

[@ddan.97]

audio and video aren't in sync. otherwise, great info

[@MrBdubsSAS]

Thanks. I have since changed my video capture software, and the sound is much better. Unfortunately, as I am now teaching math, I haven't had time to go back and correct my old physics videos... Someday.

[@splint3048]

@isaac65619 Google virtual ti calculator. It's meant for owners of the TI range of calculators but the complete working file is easily found.

[@anilsharma-ev2my]

Burnoulli theorum in work mode How much work done in this phenomenon

[@MrBdubsSAS]

Of course, by that I meant 0.16 m...

[@anilsharma-ev2my]

How much work done by whole atmospheric pressure round the globe according to energy efficiency Atmosphere energy input by sun and its volume increased and pressure decreases and displacement of air mass occurred So found that work done ?

[@monalisawithacat6059]

Good video.. can you please tell me how do I solve the problems where two different liquids are filled in the tank at different levels???

[@isaac65619]

what´s the name of virtual calculator?

[@sketsuarez]

why P1 & P2 cancle out? (in problem 2)

[@leorobinson9920]

i got a different answer for part (a) i got9.947 instead of .99 so i tried using my own answer in part (b) and got 40.01 need help with this plz

[@mohamedh.394]

Shouldn't the area of the cylinder be 2(pi)r^2? You used (pi)r^2 which is for a circle.

[@MrBdubsSAS]

HI Mo, sorry, just saw this. I assume you are talking about the first question? When we do area, we aren't looking for the surface area of a cylinder. We are looking for the cross sectional area through which the fluid must pass, which is the circle on the end. As a side note, if you are finding the surface area of a cylinder, it is 2(pi)r^2 + 2(pi)r*h, as you need to include the side part between the circles as well...

[@Megha-rv2hd]

App na kis book sa yah question karvaya hai?? Plz tell me book name and author 's name??? Plzzzz

[@peachybywater92]

This question is not from a textbook, it is the note packet that we used in our AP class. I believe you can get similar questions in the Cutnell/Johnson Physics 10th Edition Textbook.

[@Karim7097]

cm? It is either mm or m in engineering

[@MrBdubsSAS]

Hi Karim, very true. Though at the time I was teaching High School AP Physics, and part of the purpose of this problem was to work through the unit conversions!

[@SamLaseter]

Shouldn't acceleration due to gravity (g) be negative?

[@geospizamahato250]

Sam Parker no it's must not be negative I guess

[@Itsmithu2808]

ok.... got it

[@0091paddy]

Part C - i put into my calculator and got a completely different number :S

[@xXdJdAvEP]

0.16 M :)