Page 70 - E-modul Mekanika Teknik 2 Kelas X Sekolah Menengah Kejuruan

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MOMEN KELEMBAMAN/INERSIA

Jarak Z1 & Z2 akan sumbu x dan y:
b1 = 5 cm – 1 cm = 4 cm
b2 = 0 cm
b3 = 5 cm – 1 cm = 4 cm
a1 = 5 cm – 3 cm = 2 cm
a2 = 0 cm
a3 = 5 cm – 3 cm = 2 cm
Momen Inersia akan sumbu x:
Ix = I2x + Fb 2
4
2
4
2
3
Ix1 = 1/12 . 6 cm . (2 cm) + 12 cm . (4 cm) = 4 cm + 192 cm = 196 cm 4
2
3
4
Ix2 = 1/12 . 2 cm . (6 cm) + 12 cm . (0 cm) = 36 cm + 0 cm = 36 cm 4
2
4
4
3
Ix3 = 1/12 . 6 cm . (2 cm) + 12 cm . (4 cm) = 4 cm + 192 cm = 196 cm 4
2
2
4
4
Jadi Ix = 428 cm
Momen Inersia akan sumbu y:
Iy = I2y + F.a 2
2
3
4
Iy1 = 1/12 . 2 cm . (6 cm) + 12 cm . (2 cm) = 36 cm + 48 cm = 84 cm 4
2
4
4
4
4
2
3
Iy2 = 1/12 . 6 cm . (2 cm) + 12 cm . (0 cm) = 4 cm + 0 cm = 4 cm
2
Iy3 = 1/12 . 2 cm . (6 cm) + 12 cm . (2 cm) = 36 cm + 48 cm = 84 cm 4
4
3
2
2
4
Jadi Iy = 172 cm 4

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