Page 68 - E-modul_Mekanika Teknik 2_SMK_Kelas X

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MOMEN KELEMBAMAN/INERSIA

2
4
2
4
3
Ix1 = 1/12 . 2 cm . (6 cm) + 12 cm . (2 cm) = 36 cm + 48 cm = 84 cm 4
4
4
3
2
2
Ix2 = 1/12 . 6 cm . (2 cm) + 12 cm . (2 cm) = 4 cm + 48 cm = 56 cm 4
Jadi Ix = 140 cm 4
Momen kelembaman/Inersia terhadap sumbu y:
Rumus : Iy = I2y + F.a 2
4
2
2
3
4
Iy1 = 1/12 . 6 cm . (2 cm) + 12 cm . (1 cm) = 4 cm + 12 cm = 16 cm 4
4
3
2
2
4
Iy2 = 1/12 . 2 cm . (6 cm) + 12 cm . (1 cm) = 36 cm + 12 cm = 48 cm 4
4
Jadi Iy = 64 cm

2. Perhitungan Soal Nomor 2

Z1
I F1

F1 II

6 cm
9 cm Z2 F2

F2

5 cm
Z3
1 cm III F3 2 cm

3 cm F3
5 cm
7 cm
4 cm 2 cm 4 cm

Gambar 51. Perhitungan Latihan Soal Nomor 2 Momen Inersia

Perhitungan:
F1 = 6 cm . 2 cm = 12 cm
2
F2 = 2 cm . 6 cm = 12 cm
2
F3 = 6 cm . 2 cm = 12 cm
2
2
∑F = 36 cm
Koordinat titik berat masing-masing bagian penampang:
X1 = 3 cm, Y1 = 9 cm
X2 = 5 cm, Y2 = 5 cm
X3 = 7 cm, Y3 = 1 cm

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