DEPARTMENT O 



Mu , Structure 



PROBLEMS IN STRENGTH OF 

 MATERIALS 



I. TENSION, COMPEESSION, AND SHEAE 



1. Find the breaking unit-stress for a round rod 1^ inches in 

 diameter which breaks with a tensile load of 67,500 pounds. 



2. If a wrought-iron bar 2 x 1-J inches section area breaks under 

 a tensile load of 125,000 pounds, what load will break a wrought- 

 iron rod 1| inches in diameter ? 



3. What should be the diameter of a round cast-iron bar which is 

 subjected to a tension of 30,000 pounds, if the unit- stress is 2400 

 pounds per square inch ? 



4. Calculate the diameter of a round wrought-iron rod which is 

 under a tension of 85,000 pounds, if the unit-stress is one half the 

 elastic limit. 



5. A piece of timber 2J- inches thick is under a tension of 9000 

 pounds. Find its width if the unit-stress is to be 30 per cent of the 

 elastic limit. 



6. A bar of structural steel 1J inches in diameter ruptures under 

 a tension of 100,000 pounds. Find the ultimate tensile strength of 

 the bar and the tensile. force which will rupture a bar of the same 

 steel whose section area is 2^ x 3 inches. 



7. Find the greatest tensile force a copper wire 0.2 inch in 

 diameter can stand without breaking. 



8. Calculate the size of a square wrought-iron bar to stand a pull 

 of 3000 pounds without breaking. 



9. A steel specimen 0.802 inch in diameter and 8 inches long, 

 in an experiment with the testing machine, reached the elastic limit 

 under a tensile force of 24,640 pounds and ruptured under a load of 

 34,800 pounds. The length of the bar at the elastic limit was 8.0122 

 inches and at rupture 10.25 inches. Calculate the elastic limit, the 



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