BCE Mechanics of Materials 2

Question 1

In the flexure formula σ = My/I, what does the variable 'y' represent?

Accepted Answer

The distance from the neutral axis to the point of interest

Answer

The span length of the beam

Answer

The depth of the beam section

Answer

The distance from the support to the load

Question 2

For a simply supported beam of span L carrying a central point load W, the maximum bending moment is:

Accepted Answer

WL/4

Answer

WL/2

Answer

WL/8

Answer

WL

Question 3

The section modulus Z of a solid rectangular section (width b, height h) is:

Accepted Answer

bh²/6

Answer

bh³/12

Answer

bh²/4

Answer

bh³/6

Question 4

For a rectangular beam cross-section, where does the maximum shear stress due to transverse loading occur?

Accepted Answer

At the neutral axis

Answer

At the top and bottom extreme fibers

Answer

At the quarter-depth points

Answer

Uniformly throughout the section

Question 5

The second moment of area (moment of inertia) of a solid circular cross-section with diameter D about a centroidal axis is:

Accepted Answer

πD⁴/64

Answer

πD⁴/32

Answer

πD³/32

Answer

πD⁴/16

Question 6

For a simply supported beam carrying a uniformly distributed load w (per unit length) over its full span L, the maximum bending moment is:

Accepted Answer

wL²/8

Answer

wL²/4

Answer

wL²/2

Answer

wL/4

Question 7

The neutral axis of a beam cross-section under pure bending is the locus of points where:

Accepted Answer

Bending (normal) stress is zero

Answer

Shear stress is maximum

Answer

Deflection is maximum

Answer

The section modulus equals zero