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A material has Poisson’s ratio equal to 0.5. When a tensile force is applied to a wire made of this material, its cross-sectional area decreases by 4%. The corresponding percentage increase in its length is:

1. 1%
2. 2%
3. 2.5%
4. 4%

Correct answer: 4%

Solution

When Poisson's ratio is 0.5, it indicates that the material is incompressible, meaning that any decrease in cross-sectional area directly corresponds to an equal percentage increase in length. Therefore, a 4% decrease in area results in a 4% increase in length.

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