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Comparing elastic (bending) strength for rectangular beams of different widths Beam A and Beam B have the same length and depth d; Beam B has double the width b of Beam A. Determine how the elastic bending strength of Beam B compares to Beam A. Choose the correct option.

Difficulty: Easy

same
double
four times
six times

Correct Answer: double

Explanation:

Given
Rectangular section: width = b, depth = d. Beam B has width 2b, same d.

Concept/Approach
Elastic bending strength ∝ section modulus Z.
For a rectangle: Z = bd²/6.

Step-by-step
Z_A = b d²/6Z_B = (2b) d²/6 = 2 × (b d²/6) = 2 Z_A

Conclusion
Strength (at same allowable stress) doubles.

Final Answer
double

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