2C4 QUESTIONS AND PROBLEMS. CHAPTER IX. 



1. A block 15 inches square is subjected to a load of 90,000 

 Ibs., the resultant of which lies 2 inches from the center, on a line 

 through the center parallel to one side. Find the maximum and 

 minimum stresses. 



2. In problem 1 where should the load be placed in order 

 to have a tensile stress of 100 Ibs. per sq. in. on one side? What 

 is the maximum compressive stress in this case ? At what points 

 is the stress zero V 



3. A pier 2 ft. square and 6 ft. high is subjected to a direct 

 load of 180,000 Ibs. at the center and a horizontal force at the 

 top. What is the greatest value of this horizontal force in order 

 that no part of the pier shall be in tension ? With this force act- 

 ing, what is the maximum compressive stress in the pier ? 



4. A cast iron block 4 in. square has its resultant load at 

 the middle. Compare its strength with that of a block 4 in.X6 in. 

 with the load 2 in. from a 4 in. face. 



5. A solid steel rod 2 in. in diameter and 5 ft. long is sub- 

 jected to a compressive stress of 50,000 Ibs. 0.1 in. from the cen- 

 ter, the ends being pivoted. Find the deflection at the center and 

 the maximum unit stress. 



6. A 6 in.X4 in.XMz i n - angle 5 ft. long is used as a column 

 with pin ends. Find the total safe load concentrically placed, by 

 Euler's formula, with a factor of safety of 5. 



Calculate the safe load of a similar angle 10 ft. long. 



Compare these results with the values obtained from Rankine's 



formula, with constants as given in the ' ' Cambria ' ' handbook. 



7. Find the safe load with a factor of safety of 5, on a 

 latticed column made of two 10 in. 20 Ib. channels 6 in. back to 

 back, toes turned out, ends fixed, and length 20 ft. 



8. Find the safe load on a 12 in. 40 Ib. I beam, 16 ft. long 

 medium steel used as a column, by Rankine 's formula, using the 

 constants of the Philadelphia building laws. Solve the same by 

 the Straight Line formula of the New York building laws. (See 

 "Cambria.") 



9. Find the safe load on a cast iron column 10 ft. long, 8 in, 

 outside diameter, Qy 2 in. inside diameter, by the New York laws 

 and the Philadelphia laws. 



10. Find the safe load on a 10 in. round yellow pine col- 

 umn, 12 ft. long with flat ends by the New York formula. 



11. What is the diameter of a solid medium steel rod 5 ft. 



