PE exam practice - What is the answer?

What is the answer? question 2

What is the answer image

Today’s What is the answer question comes from mechanics of materials.   Here we go…

A 1/2 inch diameter steel rod is stretched between two fixed points.  At a temperature of 72 degrees Fahrenheit the tensile load in the rod is 850 pounds.  At approximately what temperature (in degrees Fahrenheit) will the stress in the rod be zero?

A.  85

B.  95

C.  105

D.  115

What is the answer

Work the problem and comment below with your answer.  As always… please share this post with others!  After all of that please head on over to the Mechanical PE Academy Facebook page and give it a like!

6 comments on “What is the answer? question 2

  1. The approximate answer is 95° F. If stress goes to zero, and assuming E=29E6 psi and alpha=6.5E-6 in/(in-°F): delta_th=delta_st》alpha(DeltaT)=P/(AE), plug n chug and solve for T.

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