10 PEOBLEMS IN STRENGTH OF MATERIALS 



98. What internal pressure will burst a cast-iron sphere 24 inches 

 inside diameter and 4 inch thick ? 



o 



99. A cast-iron sphere 10 inches inside diameter and ^ inch thick 

 sustains an internal pressure of 200 pounds per square inch. Find 

 the factor of safety. 



100. What should be the minimum thickness of a cast-iron sphere 

 8 inches inside diameter to safely withstand a steady internal pressure 

 of 200 pounds per square inch? 



101. A force of 500 pounds is applied to the piston-head of a force- 

 pump 1 inch in diameter, which transfers its pressure to a hollow 

 cast-iron sphere 10 inches in diameter. What should be the thickness 

 of the sphere for a factor of safety of 6 ? 



102. Determine the pressure for a factor of safety of 5 in a 60-inch 

 wrought-iron boiler shell J inch thick, if the efficiency of the joint is 

 70 per cent. 



103. Find the thickness of plates for a boiler shell 8 feet in diam- 

 eter to work at a pressure of 160 pounds per square inch, if efficiency 

 of joint is 80 per cent, and stress in plates is 5 tons per square inch. 



104. A wrought-iron boiler shell 4 feet in diameter sustains a steam 

 pressure of 120 pounds per square inch. If the efficiency of the riv- 

 eted joint is 60 per cent and the stress steady, what should be the 

 thickness of the plate? 



105. A wrought-iron cylinder 20 inches inside diameter and J inch 

 thick has hemispherical ends ^ inch thick. Determine the factor 

 of safety if it is subjected to an internal pressure of 600 pounds per 

 square inch. 



106. A wrought-iron pipe 10 inches inside diameter and | inch 

 thick is 100 feet long when empty. What will be its length when 

 subjected to an internal pressure of 500 pounds per square inch? 



107. A wrought-iron pipe 5 inches inside diameter weighs 12.5 

 pounds per linear foot. Find its thickness and the internal pressure 

 it can carry with a factor of safety of 8. 



108. Find the elongation and factor of safety for a 6-inch wrought- 

 iron pipe -^ inch thick and 50 feet long, under an internal pressure 

 of 200 pounds per square inch. 



NOTE. The following problems are to be solved by Stewart's formulae.* 

 * Transactions of the American Society of Mechanical Engineers, Vol. XXVII. 



