What Is the Normal Stress in a Prismatic Bar Under Tension?

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SUMMARY

The normal stress in a prismatic bar under tension can be calculated using the formula stress = force / area. In this case, with a force of 100 N and a cross-sectional area of 5 cm², the correct calculation involves converting the area to m², resulting in a stress of 20,000 Pa or 20 kPa. The confusion arose from incorrect unit conversions and misunderstanding the derived units of a Pascal, which is defined as N/m². The bar is not supported in the middle, and the applied force remains 100 N.

PREREQUISITES
  • Understanding of normal stress and its calculation
  • Knowledge of unit conversions between cm² and m²
  • Familiarity with the concept of tension in structural mechanics
  • Basic grasp of derived units, specifically the Pascal (Pa)
NEXT STEPS
  • Study the principles of normal stress in materials science
  • Learn about unit conversions in engineering contexts
  • Explore tension and compression in structural analysis
  • Review the properties and applications of the Pascal unit
USEFUL FOR

Engineering students, structural analysts, and anyone studying mechanics of materials will benefit from this discussion.

Baumer8993
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Homework Statement


In a prismatic bar (same cross sectional area throughout the entire length), the load applied to both ends is 100 N causing the member to be in tension. If the cross sectional area of the member is
5 cm2. What is the normal stress in the in kPa?


Homework Equations


stress = force / area


The Attempt at a Solution



I first tried without looking at the units, and got 20, which is wrong. I next tried converting everything to m2 to get the answer is pascals the convert to kPa. I got 200 for my second answer. What am I doing wrong? This seems like such a simple problem!
 
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What are the derived units of a Pascal? Are they N/m^2 or N/cm^2?
 
They are N/m^2. I used an online converter to check, so I confused about what I did wrong.
 
Is the bar supported in the middle? If so, should the force be 100 or 200 N?
How did you get 20?
 

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