mechanics of materials
posted by dmkp .
The second moment of area of a hollow cylindrical beam with an inner radius of 18mm and an outer radius of 20mm is equal to
A) 2.7x109m 4
B) 4.3x108 m 4
C) 7.9x10  13m 4
D) 2.7x10 3 m 4

J=π(D²d²)/32 =...