1. He 40 kenimika ka lōʻihi o ke kila ma 20 o C. ʻO ke koina o ka hoʻonui linear no ke kila he 12 x 10 -6 (C o ) -1 . ʻO ka hoʻonui ʻana o ka lōʻihi a me ka lōʻihi hope loa i ka wā ma 70 o C e…
ʻIke ʻia:
ʻO ka loli o ka mahana ( ΔT ) = 70 o C – 20 o C = 50 o C
ʻO ka lōʻihi mua (L 1 ) = 40 kenimika
ʻO ke koina o ka hoʻonui linear no ke kila (α ) = 12 x 10-6 ( C o ) -1
Makemake ʻia: ʻO ka loli o ka lōʻihi ( ΔL ) a me ka lōʻihi hope loa ( L2 )
Lōlā:
a) Ka loli o ka lōʻihi ( ΔL)
ΔL = αL 1 ΔT
Δ L = ( 12×10 -6 o C -1 )(40 knm)(50 o C)
Δ L = (10 -6 )(24 x 10 3 ) knm
Δ L = 24 x 10 -3 kenimika
Δ L = 24 / 10 3 kenimika
Δ L = 24 / 1000 kenimika
Δ L = 0.024 kenimika
b) Ka lōʻihi hope loa (L 2 )
L 2 = L 1 + ΔL
L 2 = 40 kenimika + 0.024 kenimika
L 2 = 40.024 kenimika
ʻAʻole maopopo
2. He koʻokoʻo hao i hoʻomehana ʻia mai 30 ° C a i 80 ° C . ʻO ka lōʻihi hope loa o ka hao he 115 cm a ʻo ke koina o ka hoʻonui linear he 3×10−3−1−2 . He aha ka lōʻihi mua a me ka loli o ka lōʻihi o ka hao?
Lōlā:
ʻO ka loli o ka mahana ( ΔT) = 80 o C – 30 o C = 50 o C
ʻO ka lōʻihi hope loa (L 2 ) = 115 kenimika
ʻO ke koina o ka hoʻonui linear ( α) = 3 × 10 -3 o C -1
Makemake ʻia: ka lōʻihi mua (L 1 ) a me ka loli o ka lōʻihi ( Δ L)
Lōlā:
a) Ka lōʻihi mua (L 1 )
ʻO ke ʻano o ka loli o ka lōʻihi no ka hoʻonui linear:
ΔL = αL 1 ΔT
ʻO ke ʻano o ka lōʻihi hope loa :
L 2 = L 1 + ΔL
L 2 = L 1 + α L 1 ΔT
L 2 = L 1 (1 + α ΔT)
115 knm = L 1 (1 + (3.10 -3 o C -1 )(50 o C)
115 kenimika = L 1 (1 + 150.10 -3 )
115 kenimika = L 1 (1 + 0.15)
115 kenimika = L 1 (1.15)
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L 1 = 115 kenimika / 1.15 L 1 = 100 kenimika b) ka loli o ka lōʻihi ( ΔL ) Δ L = L 2 – L 1 ΔL = 115 kenimika – 100 kenimika Δ L = 15 kenimika |
ʻAʻole maopopo
3. Ma 25 o C, ʻo ka lōʻihi o ke aniani he 50 kenimika. Ma hope o ka hoʻomehana ʻana, ʻo ka lōʻihi hope loa o ke aniani he 50.9 kenimika. ʻO ke koina o ka hoʻonui linear ʻo α = 9 x 10 -6 C -1 . E hoʻoholo i ka mahana hope loa o ke aniani…
ʻIke ʻia:
ʻO ka lōʻihi mua (L 1 ) = 50 kenimika
ʻO ka lōʻihi hope loa (L 2 ) = 50.09 kenimika
ʻO ka loli o ka lōʻihi ( Δ L) = 50.2 kenimika - 50 kenimika = 0.09 kenimika
ʻO ke koina o ka hoʻonui linear (α) = 9 x 10 -6 o C -1
ʻO ka mahana mua (T 1 ) = 25 o C
Makemake ʻia: ʻO ka mahana hope loa (T 2 )
Lōlā:
ΔL = α L 1 ΔT
ΔL = αL1 ( T2 – T1 )
0.09 kenimika = ( 9 x 10 -6 o C) (50 kenimika )(T 2 – 25 o C)
0.09 = (45 x 10 -5 )(T 2 – 25)
0.09 / (45 x 10 -5 ) = T 2 – 25
0.002 x 10 5 = T 2 – 25
2 x 10 2 = T 2 – 25
200 = T 2 – 25
T 2 = 200 + 25
T 2 = 225 o C
ʻO 225 ° C ka mahana hope loa .
ʻAʻole maopopo
4. ʻO ka lōʻihi mua o ka metala he 1 mika a ʻo ka lōʻihi hope loa he 1.02 m. ʻO ka loli o ka mahana he 50 Kelvin. E hoʻoholo i ke koina o ka hoʻonui linear!
ʻIke ʻia:
ʻO ka lōʻihi mua (L 1 ) = 1 mika
ʻO ka lōʻihi hope loa (L 2 ) = 1.02 mika
ʻO ka loli o ka lōʻihi ( Δ L) = L 2 – L 1 = 1.02 mika – 1 mika = 0.02 mika
ʻO ka loli o ka mahana (ΔT ) = 50 Kelvin = 50 o C
Makemake ʻia: ʻO ke koina o ka hoʻonui linear
Lōlā:
ΔL = αL 1 ΔT
0.02 m = α (1 m ) (50 o C)
0.02 = α ( 50 o C)
α = 0.02 / 50 o C
α = 0.0004 o C -1
α = 4 x 10 -4 o C -1
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