Ka hoʻonui laina - nā pilikia a me nā hoʻonā

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)

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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