how are you guys welcome back to my YouTube channel uh do not forget to subscribe right and share these videos to your fellow classmates so today I want us to deal multaneously so with the centrifugal pump and ventilation we have centrifugal pump and ventilations right um so the things that you must understand now we have a cfal pump okay I want us to deal here the centrifugal pump the most important thing you must noce that by by force for argument Force let us want the force force to calculate the force or tangential force can see tangential it's either tangential tangential force or the force um this you know that if you know force is what rep density multiply by what by rate of flow MTI by the velocity right this will be in Newtons this is the formula to calculate what the force on Cal when sh force of course use this formula right so another important thing you must know that this is your it's your Force right in Newton this is a is a density right so so we have this there which is fine now you must know you'll be given this stru okay let me just break down let me just break down to calculate this is the false let's go out let us next let us check power right power your power now we're looking at power to calculate power you must know when you're taking this usually this is a power power but must be specific this is what um this is a power right but now let's say now you want um okay let's say now you want this it's an output power you want an output power right so if you want output power you must make the sub of the formula you know that okay let me break it so simple let me make like let me do like this so that you understand okay efficiency remember this is an efficient note this is an efficient of what of the pump it's just an efficient equal to the output will be equal to Output poweride by input yeah right input power this is of the motor then that is an output power obviously this you multiply this by 100 isn't it multiply this by [Music] 100% this I'll mtip this by 100 either way 100% or 100 is fine then now this is what it's an equation to calculate power this is either will be in right you can write in kilow if you want any of this this is not that is power right when you're dealing with the cfal pumps right now remember this is an efficien of the pump now we have the monometric efficiency this monometric this is a manometric manometric monometric efficiency this is the pump this is an efficienc of the pump actually efficiency of the pump so you see the difference here this is the monometric efficients youve given a monometric monometric is just a theoretical as another way you can see theoretical efficient this is just a theoretical efficient but you call it monometric power here right just a theoretical this you must know this is equal to this is equal to G MTI by H over U thought right multiply by v w right I will tell you what is this okay this we call this it is a manometric efficient how we calculate manometric efficient we use this formula this will be man this that is manometric man metric one or can say de retical efficient this is a theoretical efficiency I hope you understand theoretical efficiency right monometric efficient so you must know this high this H there this H that H is equal to what a total head generated this is the total head generated that is what our H total h generated right and then the total head generated it's actually actual head is not a theoretical head this one it's a actual head is another is we can say actual head generated okay this okay let me just stop there let me just not confuse you uh that one will be total head generated right hope we understand each other to generated you find monometric this is monometric right how you find the monometric but you can also manipulate this formula if you given to find um this is the it is the impeller velocity right this one um to find u w we can say that can multiply there we have G over monometric v w can have that right it's another way to calculate that the peripheral speed that is the peripheral speed way that speed must is the speed the speed obvious limit pereral right so you must know that [Music] um um W okay no problem about that you know that we got those things there um so you must know what does each of this thing G is the gravitational force this is a gravity which is 98 it's a gravity acceleration due to gravity this is the wheel the wheel velocity for tangential we can see tangental velocity or the tal velocity is called we use this two ways to describe that it's all velocity or tangential velocity right so this is the typically you must know this stuff right we have this stuff here now what about this what peripheral velocity peripheral velocity is equal to this formula must be PI right MTI by D n/ 6 must know this time it we always use the out we don't use the we use the outlet not the inlet must always be an outlet D of the impel this is an imp diameter it's an out outer diameter when for use the outter Outlet diameter this is an outlet diameter of what impel impel right so this you must know this diameter Outlet diameter this is off ined it's an outlet there's no way in this question you will use Inlet diameter they can confuse you and give you two diameters there maybe the question they give you two diameters then you you get you just what is going on now and you used to be given one time but otherwi if they give you two time take the out the out time meter don't take the internal take the outer diameter yeah the outer diameter not we don't use internal here we use the outer Dieter which is you can say the outer Dieter we use the outer one right we have this so far now we also have our X the difference there must be equal to peripheral diameter peripheral speed or velocity Min minus we have this right minus is what can minus the one of velocity of the wheel wheel velocity then this is the difference just X is a difference you must this typically you must know this formulas so another formula you must know right here you can another there oh we must know another formula you can screenshot here I will erase let me give you just minut just screenshot there can pause and screenshot those formas okay I hopefully can SW allow me to raise here this is a false screenshot this allow me to erase here so I am done there okay eras you have this you can make if you if you want the output power you can make either of these two you can find either of these two the we can make either of these two the subject form if you have want the output power we can use this but okay it's fine if you given this if you check the efficient if you given this efficiency now let's say now you want the output power I want you to not know this want the output power cannot just use one the output power now you are only G in the equation you only given monometric efficients you don't you're not given the pump efficiency this is the different two things this are difference monometric efficiency and pump efficiency is not the same so let say we given a monometric efficiency if you're given monometric efficiency right if you're gric then you want to calate Output power the output power will be equal to you know almost the formula of the power is density right multip by two right now the head that you'll use here will be theoretical head use a theor theal head theoretical head right you use theoretical head because you have what monometric remember monometric is theoretical you use theoretical head but do not confuse this is not a theoretical head this is what total head generated on this formula of demetric but you will have to use theoretical head what is theoretical head let me erase you allow me how can you find theoretical head theoretical head you must know again monometric monometric efficiency is equal to Total head generated this H over theortical head right over theortical this is what over theortical theortical head this remember this is what we say is what is total head generated total head generated you see if you given monometric right there you want the output power you will use the monometric effici you will use the monometric head for an example in this in your book will be given is this activity here me to check exercise here let us check exercise would be given this exercise here I want you to check something if you given this exercise here you see this exercise three here they can ask you C C say the in the output power of the motor driving pump right but if you check the question here if you check the question you see what what do they want here H example they want the output power of the motor driving pump they want it but check any your questions you have you see we have given what monometric efficient not the pump efficient so you must use which formula here the one that I'm discussing about you must use the head theoretical head right so we must use theoretical head you see p calculate theoretical head you should use the theoretical head because you have given what the the monometric monometric efficiency not the pump efficiency right so Ste here we have given manometric efficiency so you must see you must know what you we have given so this is the manometric is not an an efficiency right of the pump good so so so so as I've shown you there you'll use that for more in the last question there this because of given monometric just showing you that so we have this is the formulas that we supposed to use right you must know these formulas let me get something to wipe here must use this formulas screenshot here um so we know these formulas right let me Erase here again allow me to erase here me to erase here if you given two the rate of flow must be equal to the area right but now you multiply always when you're dealing with F this will be V F0 right be velocity flow you'll multiply by this by the velocity flow you will use velocity flow velocity flow and you must know the output power the original output power if you have given the pump efficien again is it's I said is power it's output power over input M 100% right but must know this is the same as density MTI by the rate of flow MTI what H this is the total head generated not the theoretical this must be total head generated not theoretical divide this by the input power you multiply this by your 100% is it it this by 100 that it's an efficiency of the pump so must understand these formulas you must know them and then you must understand what you are what are you doing there so so the structure that you'll be dealing with is this structure um let me just write here let me erase I hope you guys you can take pick there can take you can screenshot there so that you'll understand that you can screenshot fine fine hopefully screenshot let me Erase here tired guys okay this okay must know this triangle I want it to be large enough that is I erased you'll draw this triangle first you'll construct this triangle right after constructing this triangle from the from the edge bottom edge of this triangle draw a diagonal you know diagonal line is a line like this always at the edge through the tech line and let it touch there so you see have how many triang one two three about the whole one you draw triangle then from the edge here draw a line until it touches the hypotonous length right must have this triangle must no by hit will be luck if you are given but must not triangle isn't it you must know this triangle so must know here must know this is V flow the one that I'm talking about is V flow here from here until the this distance here until the let me just write here this distance here must be X right this distance here must be V of the wheel but the distance from here until there from the bottom this distance like this until there at the bottom you must calculate this represent the peripheral velocity but from here here and there here and there it's what wheel velocity from from here until here and there it's X is X here we have this is an inlet Ang just it's a Theta this is five look this I just like this is not the same you see it horizontal it's a circle with a horizontal line but five with what vertical line so this is not the same thing here we say just say use a vertical line there have this that angle there right then here we have F but most of the time this will not work this is R they won't ask you about this most of the time right we have this isn't it so since we have this let's say now they want must know that when they will ask you most of the time about the outlet angle when you want the outlet angle five will be use your triang look this is a triangle right this is what it's opposite that is a and what is that is turn if you know your math canot teue math that will be that will give us what turn right turn what T5 an outl equal to what opposite over CH which is what is V flow over X right must know this form you can just use the triangle then you know when you want this take the inverse tent like this over X right this is what it's an outlet angle of the outlet outlet angle of impel this is an out angle of the impeller this is the inlet angle of the Imp know this triang then you're done done you're good to go I said always any of the question I said the D that you use the D must be if they give if the question you have given one time use it if the question you given two dieters take the one the out I hope you know the outlet one not the inlet one the external in other words I let EXN is the same thing you must know distract I heard just simple you see just throw you throw the triangle from the corner the bottom corner just throw cor then be nice so this is what it is I've just explained this here it's an explanation isn't it right yeah let me erase there yeah yeah so that side we have ventilation I was just explaining that side have a ventilation but you can just look for example just example but you're not done here yet okay the last one for you must know is to calculate the talk talk is the last one here talk we know what what is talk talk is in it is force force multiply by what by R which is the radius but now we know that force of this we know we've talked about dealing with the p right that for tal aage for is up to you want aage you can call it aage but okay let me just sayal okay let me just say aage Force there multiply by this is right radius but you know as you will be given talking about imp here imp right imp [Music] diameter always with Outlet diameter or external diameter we'll be looking at external Dieter we know this will divide by two take the Imp Dieter can see just let me just say d imp diameter you divide this by two that it should be R now since you know our force is density MTI by what velocity this I forgot to explain this must be velocity flow right the flow velocity flow in it so you multiply this by T 2 this is what you must know this is talk Newton meter meter that is talk talk it just talk no this stuff simple stuff right so yeah just break this so for the S let us just look the example that is on your Facebook I'm feeling tired I cannot write that example here I just show you guys then you can do only two three questions there uh only two three question only two only two three question let me just say we just talked about talk okay may this is a V flow right oh no cannot be V flow sorry guys not V flow I'm tired I said is will force of theer two I know here must be density Q by velocity this velocity cannot be cannot be V flow sry guys must be right obvious must be the one of the is must be will velocity isn't it must be velocity cannot be by t² sorry make made a mistake there cannot be that it's impossible V flow cannot be V flow cannot be V flow no no no no cannot be flow be yeah this by two yeah canot be flow so let me check your tbook okay it let me oh let me just check the example I cannot write them entire then cannot write all of it does check here example 15 c p delivers water you see the Cal pump cannot write all of this thing on the bo I'm tired centrifugal pump delivers water we have given Q There l in per minutes at the speed we given the speed and the the impeller is a diameter 370 mm you see you have given what the diameter do we have any other diameter no we've given only one time meter we've given only one time meter so you see here um the pressure exeed on the inlet of the FL you given the pressure the monometric efficient you see question one says total head generated you want Total head generated um question B the the peripheral velocity of the impy the rad the radial flow velocity obvious we know that the tangential wheel velocity the difference the outlet angle of the impeller you see that so let me just collect the data there for you done here is the data there so I've given that that you have seen that question right um that example I've just collected all of this data just collected I've just collected all of this that this ends in question ends with it ends with h but I want us we can write FH you can write FH you can write H let us add our I I want us to add the just calculate them the theoretical head also after finding the theortical head I want you to find the output power that means our equation will end I want extend calculate the theoretical head calculate the output power we should calculate also I'm just adding there let me just throw away this we no longer need this right you can put it there we know let me grab my calculator don't need that we know our stuff isn't it the we okay I know I never discuss about the we but I knew I will discuss it about now the form of the area in the P so yeah if I give you this start and I I written cical pump you just know what simply you know what what you're dealing with you're dealing with this thing here once I give you C come or you know that I'm G you Cal given only these things depending on the question you come you write here from the S cor here is V here it's X there is youu right yeah is the flow here is Outlet here is [Music] theer cool isn't it fa a want us to calculate this or just take let us calculate VW even this is data using this dat I want do to calculate that okay and just say number one us to calculate U right the peripheral velocity leaving remember external peripheral velocity of water leaving is leaving the imper remember theit external here the only flow is the one that is entering you know that so according to the question that you've given we know this is what is pi di over the speed 6 right if this is given in what in minutes but if it's given in seconds do not you do not include six but because you're given this in minutes okay let's check this is pi have dier here is dier you divide this by 3 divide this by multip this by 10us 3 you know is dividing then you have 0 comma [Music] 375 the speed there is 4 1 0/ 6 just get our V say Pi into say Pi 0375 14 1 this is one here divide this by 60 the take here is 27 comma 6 68 27 6 85 this must be me/ second this must be me m/ second right we have decent m per per second hopefully right now want for the argument s we are we have that I can say number two let's calculate the total head the total head generated total head we know this is is what we given a pre total head you'll get from pre always there's no way you'll get it from PR this is total head total head generated want to Cate the total head generated this will be PR we know that PR will be density G and is H generated want that H make H the subject of formula [Music] density that is flowing water density okay this is the pressure given pressure which is 28a [Music] 204a 5 * 10^ 3 over density of water is 981 then I punch this on my calculator let me see what I will get there okay 28 right 4 comma 5 28 4 okay 284 comma 5 * 10 the power 3,000 * 91 C 29 001 yes remember we rounded to three decimal places we round these two three decimal places since we R this to three decimal places let us if you run this to decimal places is 29 [Music] 01 you can also calculate we'll also find the talk okay know what I wanted to deal with these things multaneously but let me just I will do this alone ventilation because okay I will introduce it Al I'll just introduce this at the end of this video just an intro of the ventilation you know what so that may not right so that all right cool can say okay I don't know IAS this is right like this let me just say three three we're done with this okay we go to this head yeah it's fine now I want us to calculate the theoretical head I'm just using my qu you see we have given this St but now let me just put the questions the way I like right you will he let us calculate number three the theoretical head let us find the thetical head argument theoretical head we know we have here we have given monometric efficient we know the optical head is monometric how we C this we know that monometric efficiency is total head total head generated divide by theoretical one just calculate theoretical head all right no problem 7 7/ 4 this remember percent is 100 we know this this symbol is just 100 100 but it's not only 100 it's just this symbol is is like this if you see that symbol that means when I see this symbol I just see this I see division sign and 100 always when I see the symbol this is the same as this I just see this I know must be something here but I just see this when I see the symbol right here I see division sign and here I see what 100 you know so if you given there 74 here we have given this per but I when I see that I see over 100 when I see that me I don't know to your M but what I see when I divide this I know this will be 074 so what I see there total head generated is here 29 001 vertical no cross multiply this is just a basic M let me just say t thetical head be 29 01/ 074 okay let's see what we have let me punch this on my calculate 290 01 over 074 right 39a 1 CA okay 39 righta 1 191 let us round all this on your final exam round off to three decimal places we saw that is 39a 1 191 in me also this you what an air must been me oh this will be zero cannot just be a number what I've done there this must been made cannot cannot why I cannot just say 29 only must be meter there Al so that is in meter that must be meter oh let me see what can we calculate again um you know what fine since you got this let me just say let us calculate the output power I want us to calculate the output power right yeah do calculate output Power number four it do calculate using this formation it does calculate the output power our question calculate the output power so this is an output power when we calculate output power the output power I said you must check what are you given I said there check we have given monometric deficient we not given what the pump efficien isn't it so since you're given the efficient what I've said I said we use this power power all that know that out power density gra it no it's true right you but gra it I said tell me I said what we should supposed to use there we discussed wish wish is supposed to use there supposed to use there okay let me just let me remember that a for his gravity oh his gravity to oh sorry wish head we supposed to use here remember we supposed to have had wish head is it generated total generated I've got you if you have listened I've explained right I've said this we have given what monometric efficiency since you have given monometric efficient we canot once you've given monometric efficient if you not given pump effent you cannot use this for oh dis wrong if you use this this is wrong this is pump efficient not monometric this will be wrong completely wrong zero yeah this must be oh this must be theoretical when we're dealing with monometric this must be thetical head I've talked about this so C is th000 I can simply say 10 to the^ three see, obvious it's water by 9 81 Q we given Q here but that Q you see it's in lit per minute oh my God Q it's in lit per minute 4 1 Z oh it how can we one Cub it's equal 1,000 we must know this proportion here we have given lers let us ignore here we are given what one 4 z l what about you cross multiply multiply you'll have 41 uh 4 One there is leader leader have leaders cross multiply cross multiply is it we want tell us that will be 1,000 x you divide that by th000 X will be 1 4 1,000 this will be what in Cub isn't it this is INB this is how so but now but now we have what here minutes minutes is what it's 1 minut 1 minute = to 60 seconds so we've given one minute that means it's the same as 60 seconds it's over 60 right so yeah already this it's what we have there how good it is you have this this we replace this so we've converted that we replace this that now it's in cubic over th000 this is not 100,000 we have again six is the same as what over six right yeah it's over six like this yeah isn't it it's like that so this is the same M multiply here by six then this will be cubic right so I don't know your math I don't know but is what it is so here will be one 4 1 0 over th000 6 theortical head we gotal here it is is [Music] 3991 will be output power oh hopeful you want do St pleas gu power three * 9 8 * 981 * [Music] 410 right th000 multili by 60 * 39a 1 91 we got this as you can see 934a 98 then you press engine will be what 903 5 kilow you see I just pressed engine okay you'll get this 9 03 4 comma 8 97 then you press engine here is in it this the same aside by ,000 with kilow uh this will be 9 35 this must be in kilow that it's in kilow in kilow you got this in kilowatt right we have decent kilow then this is an output power I don't know someone I don't know how I don't know how you going to calculate this if it is not this method then we are wrong right so okay did this okay for the arent sake I canot say okay I let us end we talk I wanted us to c talk but now Let Us return back okay let us calculate the what what can I say the veloc the velocity just calculate this tooc us check okay bu he want us to calculate will veloc yes Mr fluid I saw someone there just called me hey Mr fluid as do you know me yeah you're the oneing mechanics right they said yeah just call you Mr fluid I said okay so but my name is t since language is T what does mean t solution that's my name you know my name t is T then in English if you find it difficult solution this is my name right yeah this is my name he in it so this is my name so okay let us find we want V but okay we know given monometric [Music] efficient I've talked about this formula that says [Music] G ofly by we sleep so yeah just cool you want this here can make it the subject of the formula theity of the water leing the impal no when you do your ma when you do your ma know your but mine give me this I don't know yours my math the form D okay this is a total head generated not it's a total head generated substitute here right right so this is what we'll use can just here we made that subject if just shown you guys we just simply go straight forward so this c89 81 mly total here here 29 comma 01 over monometric efficiency 074 talked about here [Music] 27 685 let us check what do we get there velocity of the tangential velocity velocity exiting the inut 9 okay just a fraction 9 81 MTI by 29a [Music] 01 right uh that is 074 * 27 comma 685 right let's see what we have 13 comma 887 round this two decimal place uhhuh 13A 88 seconds remember this is a velocity m/ second what can we add what can we add today what can we add what can we add what can we add here we have done with this okay let's start calculate oh we have a lot the value of x just calculate Val of X let us find the difference there the value of x right can find the value of x simple pretty simple just like that this on the Val of X let me raise here just yeah just found let me just say six that is six on X Cate X if you know this whole distance is you that means this distance from there until there is equal to the distance here there so you can just say W plus x x the subject take this that side to change the sign right so is this the formula we use X oh he was not this is measured in me second meur in me second that means our X automatic will be measured in me per second what difference there we know this is 27 68 5us we know that yeah Isa 887 and then X cannot be negative if it is negative you are wrong this x cannot be negative whe whether you like it or not cannot be negative if your X becomes negative if you're completely wrong start a fresh h 27 comma 685 minus 13A 887 right what do we got here see 13 789 or 13 7 98 comma 7 9 8 must be me second I have this in me per second I knowbe they will give you this then the ex then you if you did not listen to me then the ex may just put another diameter it says inl maybe says 220 mm you won't even use this use the external one here may we have the external only use the external this will be just useless you don't even use it so yeah let's just write question seven what can we do question seven let us try and think okay we have this yes youate velocity that is entering theum FL velocity okay so we know that Q is equal to area MTI by flow always will be V flow cannot change this will always be V flow you want V flow B Q oh two what [Music] is okay okay I know someone will ask what is it okay let me just explain this area thing let's just do that okay area you must know under the cfal PS Cal always will be Pi MTI by WID here other student you cannot be confused let me if you know M we is the same nothing is wrong is the same as what breath WID and price is the one in the same thing you can say withd you can also say sry about that they can say with they can also say bre just the fancy way the seem like um gradient and the r in first first the same another a weight for gradient so here we and bread is a one and the same thing just the same it's like it's like beautiful and gorgeous yeah we can just say those are synonyms right synonyms if you know yeah English is synonyms right but it's mathematic synonyms yeah mathematic [Music] synonyms okay this will be area always here under this topal W by what is what I need this is an always okay this is pi what is our we is 10 10 mm here divide this by th000 then that [Music] 01 yeah you can verify that when you culate by, [Music] is not like that if took it as five yes five will be 05 you not 10 that was WR is like this 01 M this by the diameter will be 0375 0375 then mtip let's go chift chift PP by 0 01 into 0a 375 0 011 you can see what is that 0 011 rounded this two three decimal place that will be 0 01 2 right this is 0 comma 012 M squ so what about q q we know that 141 IDE this 5,000 right also we divide this by 60 yeah 1 4 1 0,00 M by 60 you see what we got so this is just 0 Comm 0 2 oh but supposed to run this to the fourm three decimal place let me just say four yeah four okay now one v v flow will be Q over area our Q is there [Music] 024 area is 01 2 then what is that this find that 0 24 over 0 012 right oh exactly two [Music] who exactly two see 2 m/ seconds remember the velocity that yeah now let us calculate the outlet angle of the inal outlet angle the outlet angle okay it does two if it flow it does two we found that this is 2 m/ second yeah me eight okay eight want this angle right Outlet angle focus on this triangle one I call this triangle one this triangle two I I like to focus on triangle one I know almost when I will use this this will be opposite so we know that you see opposite as butle here one dot then opposite is VF x 10 okay now substitute our things Z flow is two x 1 7 98 TR 8 8247 NOS the Ang is becoming decre 8 comma 2 4 7 de we have this what can we calculate number n number n number nine just calculate the talk calculate the talk shut we want to talk is number seven let us calculate the talk the talk we want the talk now let us calculate to to is for MTI by radius but now here will be impal diameter right Me 2 our for we know this is density velocity D is over two 100 is water our Q I don't remember what we call but our qu we did punch that Q There ah let me just do it first 1428 * th000 * 60 1 141 Z 14 one0 I remember we punch and when we got something like this right this so this is 0 02 35 the diameter is here 0375 by 2 and our talk, over th000 what I'm doing there th000 mly 035 * 37 that by two oh small talk there what a small talk o that is incorrect sorry guys yes velocity here the will velocity okay we can just squeeze it it's one and the same thing can multiply this I will velocity here it is 13 comma 887 can simply just calculate first remember this is multiplication put that will velocity there which is is 13 13A 887 61a 8 n yeah this is the correct one I was amazed y that was very small but but you can happen s comma 18 n not8 Newton met remember now we when we we have 018 9 then days five we round it off that will be yeah 61 this is comma 6119 Newton me so far so far this it is yeah thank you guys for your time do not forget to subscribe to my YouTube channel and stay notified whenever I post a new videos stay tuned click that notification button I'm with you guys okay the next chapter okay we'll deal with more of the question under this but I have to introduce I will introduce um ventilation in the next CH next chapter look at [Music] ventilation ventilation which is [Music] PR must be what k s v² over a such a simple thing such an easy stuff and nice stuff mechanics is nice right it's an enjoyable subject right it's an enjoyable subject PR you know this isal pral pleasure this is ma be given like just the pleasure pleasure this is in Pascal all of this thing remember it's inal K the friction Factor friction Factor we have that friction Factor this one so we have this friction Factor here s rubbing surface rubbing surface stuff right then velocity that is just the vity m/ seconds this will be M squ and definitely M squ so this is it are we not done I'm just joking guys you understand then we know this okay but s how do we calculate that s e s you must know this is the caram perimeter mtip by the length let me just write this that perimeter multip by length this is a fan DCT right fan be focusing most of the time F which is here the it's a do not you there's no something called weed parameter here there's no weed parameter not there's no we a perameter you dealing with a this is a perimeter the straight perameter if perameter from if given a square theim given a square okay let me just rectang given here we have L here we have H this H is right so the perimeter remember is the sum of the old sides so is like you're are going from this direction it's like a distance after you reach this corner you go down you reach there you go up you someone can calculate the distance that you have traveled here you see you walk you walk l h l l l h this is the one that means you sum all of these lens L plus h plus L this one plus this H so L and L is the same is 2 H and H is the same 2 H is the peram of the rectangle right of the rectangle that's the perimeter if this is the perimeter say if you can if you want to fector out 2 will be L plus h like this that's the height this the perimeter now must know the perimeter of the can be of the crosssection focus on the crosssection is the perimeter remember but now this per remember just that was only perimeter this will be the rectangle here is length this is a stocked section this crosssection see this crosssection here is a rectangle crosssection here have a circle crosssection you will have Lear but how do we calculate the parameter here of the crosssection focus on crosssection first the parameter of this of the circle the perimeter of the circle you must know perimeter of the circle simple s a um is just 2 R but what is two if you pair remember when you multiply doesn't matter if I can say I can take this two and R like this what is 2 R remember time is equal to 2 R right so this you can replace that with time that means you see this would be Pi Pi d p d simple you see the perameter of the the perimeter of the circle is pi D just write Pi Dieter simple that is the parameter right the parameter and parameter is Meed in mid so you see Square perimeter of the square remember all sides are equal when squ l l the perimeter you will travel all these sides if you travel all you will add all of these you'll have what 4 L here that means it's 4 L that is the perimeter of the square so it's simple you see so this is the perimeter but now but now s is perimeter MTI by what by land so so for an acument sake let us now say let see now our s you know this is perimeter M by land it's in now given our T they've given us the T of crosssection like this and they've given us the crosssection of a they say say 2 me then they've given us the diameter say 4 me so okay s is perimeter no perimeter is measured in meter the length is Meed in meter that is why this G when multiply this two that is why we say this is meur M squ it's because of that so okay let me put we have that right okay perimeter of this we know is what is pi this crosssection is what when you given diameter we just know if you had a diameter you know that crosssection is what of the circle p d m this by the length 4 this by two right you see 2 * 2 this is pi WR eight punch this on your calculator so they will they will give you factor but you know this K is measured Newton s right squared here right Newton s squ per met 4 like this almost this is always not always but can say is approximately to 0 07 if you not given friction V but most of the question give you friction V if you don't have is this part here okay almost but if they don't give you just leave it just like that because they may see calculate this will depend will depend so so you'll substitute that P they so you want that pressure they say you given that V me 07 given that then you substitute that I8 remember can punch this in calculator if you want um let say velocity of given 5 m/ Second you will say 5 squide by area the area we know is pi over 4 diameter know is 4 squ this you see this is just an intro you punch you get what you get here will be not will be in P so if you have given a rectangular they will tell you rectangular say you will see you hear when they say height then they come they see we you know if they see height is something then they say we you know that is a rectangle but when they give you height is like this the we with is the same you know when if you're dealing with this will be the same throughout yeah I'm just an intro but now I can remember this is the single duct I can use the fan which splits or can use a fan let's say here I have that air the air that is traveling there if the air traveling just before here it's out this let's say this can use the double can just before can use the duct can use the table T okay let me just say here okay just use the air when you travel I can use double du can say like this can use you see we have two have two split when two Branch we can have Branch we call this Branch if a branch just before this thing split the air the when split is here our I can say this is a this is B our pressure r a must be equal to the RB then we know the plure r a is k s v² right over a isal to this will have each diameter which is maybe two maybe this is 4 M right then we have k s which v² a K and K can say they the same we can cancel that we have s² a right v² over a s let say now we say here velocity we can see arent say can make them qu if you want substitute use your things here FS also you must know that Q 1 must be equal to Q2 just the ratio know this is area one by Vel one Vel two yeah if thees they can be three branches just in intro guys so thank you guys for your time uh I explain this on the next comment section it's just an intro there let me not dwell deep thank you thank you