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) 2.7x10-9m 4
B) 4.3x10-8 m 4
C) 7.9x10 - 13m 4
D) 2.7x10 3 m 4

1 answer

J=π(D²-d²)/32 =...