Ka nuipa wela Ka wela kikoʻī Ka loli o ka mahana - Nā pilikia a me nā hoʻonā

9 Ka nuipa wela Ka wela kikoʻī Ka loli o ka mahana - Nā pilikia a me nā hoʻonā

1. Ua hoʻomehana ʻia kahi kēpau 2 kg mai 50^oC i ka 100^oC. ʻO ka wela kikoʻī o ke kēpau 130 J.kg^{-1 o}C^-1. ʻehia wela ua omo ʻia e ke kēpau?

ʻIke ʻia:

Nuipaʻa (m) = 2 kg

ʻO ka wela kikoʻī (c) = 1 3 0 J.kg ^-1 C ^-1

ʻO ka loli o ka mahana ( ΔT ) = 100 ^o C – 50 ^o C = 50 ^o C

Makemake ʻia: Wela (Q)

Lōlā:

Q = mcΔT

Q = wela , m = nuipa, c = ka wela kikoʻī , Δ T = ka loli o ka mahana

ʻO ka wela i omo ʻia e ke kēpau:

Q = (2 kg)(1 3 0 J.kg ^-1 C ^-1 )(50 ^o C)

Q = (100)(1 3 0)

Q = 1 3,000 Joules

Q = 1.3 x ¹⁰⁴ Joules

ʻAʻole maopopo

2. ʻO ka wela kikoʻī o ke keleawe he 390 J/k g ^o C, ʻo ka loli o ka mahana he 40 ^o C. Inā omo ke keleawe i 40 Joules o ka wela, he aha ke kaumaha o ke keleawe!

ʻIke ʻia:

ʻO ka wela kikoʻī o ke keleawe (c) = 390 J/k g ^o C

ʻO ka loli o ka mahana ( ΔT ) = 40 ^o C

Ka wela ( Q) = 40 J

Makemake ʻia: Nui (m) o ke keleawe

Lōlā:

Q = mcΔT

40 J = (m)( 390 J/k g ^o C)(40 ^o C)

40 = (m)( 390 /k g)(40)

40 = (m)( 390 /kg )(4)

40 = (m)( 1560 /kg )

m = 40 / 1560

m = 0.026 kg

m = 26 grams

3. ʻO ka mahana mua o 20 grams o ka wai he 30 ^o C. ʻO ka wela kikoʻī o ka wai he 1 cal g ^{-1 o} C ^-1 . Inā omo ka wai i 300 calories o ka wela, e hoʻoholo i ka mahana hope loa!

ʻIke ʻia:

Nuipaʻa (m) = 20 gr

ʻO ka mahana mua (T ₁ ) = 30 ^o C

ʻO ka wela kikoʻī o ka wai (c) = 1 cal gr ^{-1 o} C ^-1

Ka wela (Q) = 300 kal

Makemake ʻia: Ka mahana hope loa o ka wai

Lōlā:

Q = mc ΔT

300 kal = (20 gr)( 1 kal gr ^{-1 o} C ^-1 )( T ₂ -30 )

300 = (20)(1)( T ₂ -30)

300 = 20 ( T ₂ -30 )

300 = 20 T ₂ – 600

300 + 600 = 20T ₂

900 = 20T ₂

T ₂ = 900 / 20

T ₂ = 45

ʻO ka loli o ka mahana he 45 ^o C – 30 ^o C = 15 ^o C.

 ʻAʻole maopopo

4. Tka loli o ka mahana o ka wai kai is 1^oC ke omo ka wai i 3900 Joules o ka wela. ʻO ka wela kikoʻī o ka wai kai 3.9 × 10³ J/kg°C, he aha ke kaumaha o ka wai kai.

ʻIke ʻia:

ʻO ka loli o ka mahana ( ΔT ) = 1 ^o C

Ka wela (Q) = 3900 Joule

^ʻO ka wela kikoʻī o ka wai kai (c) = 3.9 x 103 J/ k g°C = 3900 J/Kg°C

Makemake ʻia: Mass (m)

Lōlā:

Q = mcΔT

Q = wela , m = nuipa, c = wela kikoʻī , Δ T = ka loli o ka mahana

m = Q / c Δ T = 3900 / (3900)(1) = 3900 / 3900 = 1 kg

5. Hoʻopili ke keleawe 2-kg i 39,000 J o ka wela ma 30°C. Inā ʻo ka wela kikoʻī o ke keleawe he 390 J/kg °C, he aha ka mahana hope loa o ke keleawe…

ʻIke ʻia:

Nuipaʻa (m) = 2 kg

Mahana mua (T ₁ ) = 30 ^o C

Ka wela (Q) = 39,000 Joule

Ka wela kikoʻī (c) o ke keleawe = 390 J/kg ^o C

Makemake ʻia : ʻO ka mahana hope loa (T ₂ )

Lōlā:

Q = mc ΔT

Q = wela , m = nuipa, c = wela kikoʻī , ΔT = ka loli o ka mahana

Q = mc ΔT = mc (T ₂ – T ₁ )

39,000 = (2)( 390)(T ₂ – 30)

100 = (2)(1)(T ₂ – 30)

100 = (2)(T ₂ – 30)

50 = T ₂ – 30

T ₂ = 50 + 30

T ₂ = 80 ^o C

ʻAʻole maopopo

6. Ua hoʻomehana ʻia kahi wai 5-kg mai 15°C a i 40°C. He aha ka wela i omo ʻia e ka wai. ʻO ka wela kikoʻī o ka wai he 4.2 × 103 ^J /Kg° C.

ʻIke ʻia:

Nuipaʻa (m) = 5 kg

Mahana mua (T ₁ ) = 15°C

Mahana hope loa (T ₂ ) = 40°C

Ka wela kikoʻī o ka wai (c) = 4.2 × 103 ^J /kg° C

Makemake ʻia: Wela (Q)

Lōlā:

Q = mc ΔT

Q = (5 kg)( 4.2 × 103 ^J /kg°C)(40°C – 15°C)

Q = (5)( 4.2 × 103 ^J )(25)

Q = 525 x 10 ³ J

Q = 525,000 Joule

7. Ua hoʻomehana ʻia kahi wai 2-kg mai 24°C a i 90°C. He aha ka wela i omo ʻia e ka wai. ʻO ka wela kikoʻī o ka wai he 4.2 × 103 ^J /Kg° C.

ʻIke ʻia:

Nuipaʻa (m) = 2 kg

Mahana mua (T ₁ ) = 24°C

Mahana hope loa (T ₂ ) = 90°C

Ka wela kikoʻī o ka wai (c) = 4,200 Joules/kg°C

Makemake ʻia :: Wela (Q)

Lōlā:

Q = mc ΔT

Q = (2 kg)( 4,200 Joules/kg°C)(90°C – 24°C)

Q = (2 kg)( 4,200 Joules/kg°C)(66°C)

Q = (132)( 4,200 Joules)

Q = 554,400 Joule

ʻAʻole maopopo

8. Ua hoʻomehana ʻia kahi wai 5-gram mai 10°C a i 40°C. He aha ka wela i omo ʻia e ka wai. ʻO ka wela kikoʻī o ka wai he 1 × 103 ^cal / g r ° C.

ʻIke ʻia:

Nuipaʻa (m) = 5 grams

Mahana mua (T ₁ ) = 10 ^o C

Mahana hope loa (T ₂ ) = 40 ^o C

Ka wela kikoʻī o ka wai (c) = 1 c al/ gr°C

Makemake ʻia : Wela

Lōlā:

Q = mc ΔT

Q = (5 grams)( 1 cal/gr°C)(40 ^o C – 10 ^o C)

Q = (5)( 1 c al)(30)

Q = 150 kaloli

9. Hoʻopili ka wai 0.2-kg i 42,000 Joules o ka wela ma 25 o ^C. ʻO ka wela kikoʻī o ka wai he 4200 J/kg ^o C, he aha ka mahana hope loa o ka wai.

ʻIke ʻia:

Ka nuipa o ka wai (m) = 0.2 kg

Ka wela (Q) = 42,000 Joule

Ka wela kikoʻī o ka wai (c) = 4200 J/kg ^o C

Mahana mua (T ₁ ) = 25 ^o C

Makemake ʻia: Mahana hope loa (T ₂ )

Lōlā:

Q = mc ΔT = mc (T ₂ – T ₁ )

Q = wela, m = ka nuipaʻa, c = wela kikoʻī, ΔT = ka loli o ka mahana, T₁ = ka mahana mua, T₂ = ka mahana hope loa

Q = mc (T ₂ – T ₁ )

42,000 = (0.2)(4200)(T ₂ – 25)

42,000 = 840 (T ₂ – 25)

42,000 = 840 T ₂ – 21,000

42,000 + 21,000 = 840 T ₂

63,000 = 840 T ₂

T ₂ = 63,000 / 840

T ₂ = 75 ^o C

1. Ke hoʻololi nei i nā unahi mahana
2. Hoʻonui laina
3. Hoʻonui ʻāina
4. Hoʻonui leo
5. wela
6. ʻO ke kūlike mechanical o ka wela
7. Ka wela kikoʻī a me ka mana wela
8. Wela huna, wela o ka hoʻoheheʻe ʻana, wela o ka mahu
9. Ka mālama ʻana i ka ikehu no ka hoʻoili wela