Pemuaian adalah bertambahnya volume suatu zat karena bertambahnya suhu zat.
Muai panjang
Rumus:
L t = L 0 ( 1 + α × Δ t ) {\displaystyle \!L_{t}=\!L_{0}(\!1+\alpha \times \Delta t)}
Keterangan:
L t {\displaystyle \!L_{t}} = panjang akhir (m, cm)
L 0 {\displaystyle \!L_{0}} = panjang awal (m, cm)
α {\displaystyle \alpha } = koefisien muai panjang (/°C)
Δ t {\displaystyle \Delta t} = perbedaan suhu (°C)Contoh:
Sebatang besi bersuhu 20°C panjang awalnya 16 meter. Jika koefisien muai panjang besi adalah 0,000012/°C, Berapakah panjang besi pada suhu 120°C? L t = L 0 ( 1 + α × Δ t ) {\displaystyle \!L_{t}=\!L_{0}(\!1+\alpha \times \Delta t)}
= 16 ( 1 + 0 , 000012 × ( 120 − 20 ) ) {\displaystyle =\!16(\!1+\!0,000012\times \!(120-20))}
= 16 ( 1 + 0 , 000012 × 100 ) ) {\displaystyle =\!16(\!1+\!0,000012\times \!100))}
= 16 ( 1 + 0 , 0012 ) {\displaystyle =\!16(\!1+\!0,0012)}
= 16 × 1 , 0012 {\displaystyle =\!16\times \!1,0012}
= 16 , 0192 m {\displaystyle =\!16,0192m}
Muai luas
Rumus:
A t = A 0 ( 1 + β × Δ t ) {\displaystyle \!A_{t}=\!A_{0}(\!1+\beta \times \Delta t)}
Keterangan:
A t {\displaystyle \!A_{t}} = luas akhir (m2 , cm2 )
A 0 {\displaystyle \!A_{0}} = luas awal (m2 , cm2 )
β {\displaystyle \beta } [1] = koefisien muai luas (/°C)
Δ t {\displaystyle \Delta t} = selisih suhu (°C)Contoh:
Sebatang besi memiliki luas awal 20 cm2 pada suhu 15°C. Berapakah luas akhir sebatang besi jika koefisien muai luas besi = 0,000024/°C dan suhu akhirnya = 25°C? A t = A 0 ( 1 + β × Δ t ) {\displaystyle \!A_{t}=\!A_{0}(\!1+\beta \times \Delta t)}
= 20 ( 1 + 0 , 000024 × ( 25 − 15 ) {\displaystyle =\!20(\!1+\!0,000024\times \!(25-15)}
= 20 ( 1 + 0 , 000024 × 10 {\displaystyle =\!20(\!1+\!0,000024\times \!10}
= 20 ( 1 + 0 , 00024 {\displaystyle =\!20(\!1+\!0,00024}
= 20 × ( 1 , 00024 ) {\displaystyle =\!20\times (\!1,00024)}
= 20 , 0048 c m 2 {\displaystyle =\!20,0048cm^{2}}
Muai ruang Catatan kaki
↑ Koefisien muai luas yang nilainya 2α