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The elastic limit of brass is 379 MPa. What is the minimum diameter of a brass rod that can support a 400 N load without exceeding its elastic limit?

1. 1.16 mm
2. 0.90 mm
3. 1.36 mm
4. 1.00 mm

Correct answer: 1.16 mm

Solution

The minimum area is 400/379e6 = 1.055e-6 m²; converting this circular area to a diameter gives about 1.16 mm.

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