Does Length Affect Stress Calculation in Material Science?

  • Thread starter Thread starter twostep08
  • Start date Start date
  • Tags Tags
    Stress
AI Thread Summary
The discussion centers on calculating stress in a material given a force and cross-sectional area. The formula for stress is correctly identified as stress equals force divided by area. The length of the bar, while mentioned, is deemed unnecessary for the stress calculation itself. The resulting stress from the provided values is 5,000 pounds per square inch, which is a unit of pressure. The length may be relevant for future calculations involving strain or changes in length.
twostep08
Messages
6
Reaction score
0

Homework Statement



A bar of material is 1ft long and has a cross sectional area of 2 square inches. If a
force of 10,000 lbs is put on the bar, what is the stress?

Homework Equations



stress= force (in pounds)/ area (square inches)

The Attempt at a Solution


this seems very easy, but the "1 foot long" in the equation is throwing me off. I've never done these kind of questions before, so i don't know how to handle it. My gut is telling me to just do 10,000 / 2 = 5000 and the "1 foot long" is unnecessary info in there to throw you off, but then again, there could easily be some other calculation i need to do...Also, what unit would the 5000 be in (assuming that's the right answer). Thanks a lot (i want to make sure i know what I'm doing, so please only answer if you are 100% sure you're right)
 
Physics news on Phys.org
I'm guessing the 1 foot long refers to another part of the question where you will have to calculate the strain. (and the change in length of the bar)
The unit you get if you divide pounds by square inches is pounds per square inch. That is a unit of pressure, though I haven't used those units since about 1967!
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top