TENSION, COMPRESSION, AND SHEAR 3 



23. Find the safe steady load for a short, hollow, cast-iron column, 

 external diameter 10 inches, internal diameter 8 inches. 



24. A wrought- iron plate f inch thick requires a force of 60,000 

 pounds to punch a round hole | inch in diameter through it. Find 

 the ultimate shearing strength of the plate. 



25. Calculate the force required to punch a hole 2 inches square 

 through a cast-iron plate | inch thick. 



26. What force is necessary to punch a hole 1 inch in .diameter 

 through a wrought-iron plate | inch thick ? 



27. What must be the least diameter of a steel bolt which is to 

 safely resist a simple shearing force of 30,000 pounds? 



28. Determine the unit shearing stress tending to shear off the 

 head of a 1^-inch wrought-iron bolt under a tension of 12,000 

 pounds, if the head is | inch deep. What is the factor of safety ? 



29. A wrought-iron bolt l^ inches in diameter has a head 1^ inches 

 deep and a tension of 30,000 pounds, applied longitudinally. Com- 

 pute the factors of safety against tension and shear. 



30. Determine the depth of head for a wrought-iron IJ-inch bolt, 

 if the tensile strength of the bolt is equal to the strength of the head 

 against shearing. 



31. The diameter of a wrought-iron bolt is | inch. What should 

 be the depth of the bolt head in order that the bolt be equally strong 

 in tension and in shear ? 



32. A wooden rod 4 inches in diameter and 3 feet long is turned 

 down to 2 inches diameter in the middle so as to leave the enlarged 

 ends each 6 inches long. Will a steady tensile force rupture the rod 

 in the middle or shear off the ends ? 



33. The head of an engine cylinder, 12 inches inside diameter, is 

 fastened on by 10 wrought-iron bolts. What should be the diameter 

 of the bolts if the steam pressure is 90 pounds per square inch and 

 the allowable unit-stress is 2000 pounds per square inch? 



NOTE. The root area should be used in this problem. 



34. A cylinder 9^- inches inside diameter contains steam at 180 

 pounds per square inch pressure. The cylinder-head is held by 6 

 wrought-iron bolts placed at equal distances from each other on the 

 circumference. Find the diameter and depth of head of the bolts 

 for a factor of safety of 10 against tension and shear. 



