Exam-style question
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A steel wire has a cross-sectional area of 2.0 mm² and is subjected to a tensile force of 400 N. Calculate the tensile stress in the wire.
Model answer
What a good answer should say
- To calculate tensile stress, use the formula: tensile stress = F / A.
- Here, F = 400 N and A = 2.0 mm² = 2.0 x 10^-6 m².
- Substituting these values gives: tensile stress = 400 N / (2.0 x 10^-6 m²) = 200,000,000 Pa or 200 MPa.
Explanation
Why this works
This calculation question requires applying the formula for tensile stress. The working shows the conversion of area from mm² to m², ensuring the correct units are used in the calculation.
The final answer is expressed in pascals, which is the standard unit for stress.
Common mistake
No common mistake is linked to this question yet.