Mehlala e 5 ea Molao oa Bernoulli
1 P1 dan tao v1 ke khatello le lebelo la moea ka holim'a lepheo, P2 dan tao v2 ke khatello le lebelo la moea o ka tlas'a lepheo. Hore sefofane se nyolohe, maemo a...
A. P1 = P.2 dan tao v1 = v2
B. P1 < P2 dan tao v1 > v2
C.P1 < P2 dan tao v1 < v2
D.P1 > P2 dan tao v1 > v2
E.P.1 > P2 dan tao v1 < v2
Puisano:
Hoa tsebahala hore:
P1 = Khatello ea moea mapheong
P2 = Khatello ea moea tlas'a mapheo
v1 = lebelo la moea mapheong
v2 = lebelo la moea tlas'a mapheo
E botsitsoe :
Maemo a sefofane a ho phahama kapa sefofane se hole ke afe?
Jawab :
Molao oa Bernoulli kapa e bitsoa hantle haholo Molao-motheo oa Bernoulli e bolela hore haeba lebelo la mokelikeli le le holimo, khatello ea mokelikeli e tlase, 'me ka lehlakoreng le leng, haeba lebelo la mokelikeli le le tlase, khatello ea mokelikeli e phahame. Mekelikeli ke lintho tse ka phallang. Mehlala ea mekelikeli ke moea le metsi.
Haeba lebelo la moea le phahame, khatello ea moea e tlase, ka lehlakoreng le leng, haeba lebelo la moea le le tlase, khatello ea moea e phahame.
Ha lebelo la moya ka hodima lepheo le le leholo ho feta lebelo la moya ka tlase ho lepheo, kgatello ya moya ka hodima lepheo e ka tlase ho kgatello ya moya ka tlase ho lepheo. Hobane kgatello ya moya ka tlase ho lepheo e kgolo, kgatello ya moya ka tlase ho lepheo le yona e kgolo. Ka lehlakoreng le leng, kgatello ya moya ka hodima lepheo e nyane, kahoo kgatello ya moya ka hodima lepheo le yona e nyane (P = F/A – ha kgatello e le kgolo, P, matla a le maholo, F).
Ho sutumetsoa ha moea ka tlas'a lepheo ho hoholo, ho sutumetsoa ha moea ka holim'a lepheo ho honyenyane, kahoo ho na le matla a hlahang kapa matla a felletseng a lebisitsoeng holimo. Matla ana kaofela a lebiswa hodimo e leng se etsang hore sefofane se phahame..
bobo maemo a hore sefofane se tsoe ke P1 < P2 le v1 > v2
Karabo e nepahetseng ke B.
2.
Setšoantšong, metsi a pompeloa ke compressor ka khatello ea 120 kPa ka har'a phaephe e ka tlase (1) 'me a phalla ho ea holimo ka lebelo la 1 m/s.-1 (g = 10 ms-2 'me boima ba metsi ke 1000 kg.m-3). Kgatelelo ya metsi phaepheng e ka hodimo (II) ke….
A. 52,5 kPa
B. 67,5 kPa
C. 80,0 kPa
D. 92,5 kPa
E. 107,5 kPa
Puisano
Hoa tsebahala hore:
Radiyo e kgolo ya phaephe (r)1) = 12 cm
Radius e nyane ea phaephe (r)2) = 6 cm
Khatello ea metsi liphaepheng tse kholo (p)1) = 120 kPa = 120.000 Pascal
Lebelo la metsi liphaepheng tse kholo (v)1) = 1 ms-1
Bophahamo ba phaephe e kgolo (h)1) = 0 m
Bophahamo ba phaephe e nyane (h)2) = 2 m
Ho potlaka ka lebaka la matla a khoheli (g) = 10 ms-2
Boima ba metsi (ρ) = 1000 kg.m-3
O botsitse: Khatello ea metsi ka har'a phaephe ea 2 (p)2)
Karabo:
Lebelo la metsi ka phaepheng ea 2 le baloa ho sebelisoa Continuity Equation:
A1 v1 =A2 v2
(π r12)(v1) = (π r22)(v2)
(r12)(v1) = (r22)(v2)
(122)(1 m/s) = (62)(v2)
144 = 36 v2
v2 = 144/36
v2 = 4 m/s
Khatello ea metsi ka har'a phaephe ea 2 e baloa ho sebelisoa equation ea Bernoulli:
120.000 + ½ (1000)(12) + (1000)(10)(0) = p2 + ½ (1000)(42) + (1000)(10)(2)
120.000 + ½ (1000)(1) + (1000)(10)(0) = p2 + ½ (1000)(16) + (1000)(10)(2)
120.000 + 500 + 0 = p2 + (500)(16) + 20.000
120.000 + 500 = p2 + 8000 + 20.000
120.500 = p2 + 28.000
p2 = 120.500 - 28.000
p2 = Lipaseka tse 92.500
p2 = 92,5 kPa
Karabo e nepahetseng ke D.
3. Sheba setšoantšo se latelang!
Phaephe e kgolo e bophahamo ba dimithara tse 5 hodimo ho lefatshe mme phaephe e nyane e bophahamo ba dimithara tse 1 hodimo ho lefatshe. Sekgahla sa phallo ya metsi phaepheng e kgolo ke dikhilomithara tse 36 ka hora.-1 ka khatello ea 9,1 x 105 Pa, ha kgatello e ka hara phaephe e nyane e le 2.105 Pa, joale lebelo la metsi ka phaepheng e nyane ke…. (botenya ba metsi = 103 kg.m-3)
A. 10 ms-1
B. 20 ms-1
C. 30 ms-1
D. 40 ms-1
E. 50 ms-1
Puisano
Hoa tsebahala hore:
Khatello ea metsi liphaepheng tse kholo (p)1) = 9,1 x 105 Pascal = 910.000 Pascal
Khatello ea metsi liphaepheng tse nyane (p)2) = 2 x 105 Pascal = 200.000 Pascal
Lebelo la metsi liphaepheng tse kholo (v)1) = 36 km/h = 36(1000)/(3600) = 36000/3600 =10 m/s
Bophahamo ba phaephe e kgolo (h)1) = -4 limithara
Bophahamo ba phaephe e nyane (h)2) = limithara tse 0
Ho potlaka ka lebaka la matla a khoheli (g) = 10 ms-2
Boima ba metsi (ρ) = 1000 kg.m-3
O botsitse: Lebelo la metsi ka phaepheng e nyane (v)2)
Karabo:
Lebelo la metsi ka phaepheng e nyane (v)2) e baloa ho sebelisoa equation ea Bernoulli:
910.000 + ½ (1000)(102) + (1000)(10)(0) = 200.000 + ½ (1000)(v22) + (1000)(10)(-4)
910.000 + 50.000 + 0 = 200.000 + 500 v22 - 40.000
960.000 = 160.000 + 500 v22
800.000 = 500 v22
800.000 / 500 = v22
1600 = v22
v2 = √1600
v2 = 40 m/s
Karabo e nepahetseng ke D.
4. Setšoantšong, metsi a pompeloa ke compressor ka khatello ea 120 kPa ka har'a phaephe e ka tlase (1) 'me a phalla ho ea holimo ka lebelo la 1 m/s.-1 (g = 10 ms-2 'me boima ba metsi ke 1000 kg.m-3). Kgatelelo ya metsi phaepheng e ka hodimo (II) ke….
A. 52,5 kPa
B. 67,5 kPa
C. 80,0 kPa
D. 92,5 kPa
E. 107,5 kPa
Puisano
Hoa tsebahala hore:
Radiyo e kgolo ya phaephe (r)1) = 12 cm
Radius e nyane ea phaephe (r)2) = 6 cm
Khatello ea metsi liphaepheng tse kholo (p)1) = 120 kPa = 120.000 Pascal
Lebelo la metsi liphaepheng tse kholo (v)1) = 1 ms-1
Bophahamo ba phaephe e kgolo (h)1) = 0 m
Bophahamo ba phaephe e nyane (h)2) = 2 m
Ho potlaka ka lebaka la matla a khoheli (g) = 10 ms-2
Boima ba metsi (ρ) = 1000 kg.m-3
O botsitse: Khatello ea metsi ka har'a phaephe ea 2 (p)2)
Karabo:
Lebelo la metsi ka phaepheng ea 2 le baloa ho sebelisoa Continuity Equation:
A1 v1 =A2 v2
(π r12)(v1) = (π r22)(v2)
(r12)(v1) = (r22)(v2)
(122)(1 m/s) = (62)(v2)
144 = 36 v2
v2 = 144/36
v2 = 4 m/s
Khatello ea metsi ka har'a phaephe ea 2 e baloa ho sebelisoa equation ea Bernoulli:
120.000 + ½ (1000)(12) + (1000)(10)(0) = p2 + ½ (1000)(42) + (1000)(10)(2)
120.000 + ½ (1000)(1) + (1000)(10)(0) = p2 + ½ (1000)(16) + (1000)(10)(2)
120.000 + 500 + 0 = p2 + (500)(16) + 20.000
120.000 + 500 = p2 + 8000 + 20.000
120.500 = p2 + 28.000
p2 = 120.500 - 28.000
p2 = Lipaseka tse 92.500
p2 = 92,5 kPa
Karabo e nepahetseng ke D.
5. Sheba setšoantšo se latelang! Sebaka sa phaephe e kholo se bophahamo ba limithara tse 5 ho tloha fatše 'me phaephe e nyane e bophahamo ba limithara tse 1 ho tloha fatše. Lebelo la phallo ea metsi phaepheng e kholo ke 36 km/h.-1 ka khatello ea 9,1 x 105 Pa, ha kgatello e ka hara phaephe e nyane e le 2.105 Pa, joale lebelo la metsi ka phaepheng e nyane ke…. (botenya ba metsi = 103 kg.m-3)
A. 10 ms-1
B. 20 ms-1
C. 30 ms-1
D. 40 ms-1
E. 50 ms-1
Puisano
Hoa tsebahala hore:
Khatello ea metsi liphaepheng tse kholo (p)1) = 9,1 x 105 Pascal = 910.000 Pascal
Khatello ea metsi liphaepheng tse nyane (p)2) = 2 x 105 Pascal = 200.000 Pascal
Lebelo la metsi liphaepheng tse kholo (v)1) = 36 km/h = 36(1000)/(3600) = 36000/3600 =10 m/s
Bophahamo ba phaephe e kgolo (h)1) = -4 limithara
Bophahamo ba phaephe e nyane (h)2) = limithara tse 0
Ho potlaka ka lebaka la matla a khoheli (g) = 10 ms-2
Boima ba metsi (ρ) = 1000 kg.m-3
O botsitse: Lebelo la metsi ka phaepheng e nyane (v)2)
Karabo:
Lebelo la metsi ka phaepheng e nyane (v)2) e baloa ho sebelisoa equation ea Bernoulli:
910.000 + ½ (1000)(102) + (1000)(10)(0) = 200.000 + ½ (1000)(v22) + (1000)(10)(-4)
910.000 + 50.000 + 0 = 200.000 + 500 v22 - 40.000
960.000 = 160.000 + 500 v22
800.000 = 500 v22
800.000 / 500 = v22
1600 = v22
v2 = √1600
v2 = 40 m/s
Karabo e nepahetseng ke D.
Mohloli oa lipotso:
Lipotso tsa Fisiks tsa Tlhahlobo ea Naha bakeng sa Sekolo se Phahameng sa Thuto e Phahameng/Sekolo se Phahameng sa Mosebetsi
