52 PROBLEMS IN STRENGTH OF MATERIALS 



499. Compare the strength and stiffness of a square shaft with that 

 of a round shaft of the same material when a side of the square shaft 

 is equal to the diameter of the round shaft. 



500. Compare the strength and stiffness of a round shaft with that 

 of a square one of the same material and having the same area of 

 cross-section. 



XL COMBINED STRESSES 



501. A 12-inch steel I-beam, 40 pounds per foot, 6 feet span, carries 

 in addition to its own weight a uniform load of 1200 pounds, and is 

 subjected to an axial compression of 60,000 pounds. Find the factor 

 of safety. 



502. Find the size of a square, wooden* simple beam of 12 feet span 

 to carry a load of 400 -pounds at the middle, when it is also subject 

 to an axial compression of 3000 pounds, the maximum allowable 

 compressive stress being 1000 pounds per square inch. Neglect weight 

 of beam. 



503. Determine the factor of safety for a simple wooden beam 

 8 feet long, 10 inches wide, and 9 inches deep, under an axial com- 

 pression of 40,000 pounds, and bearing a total uniform load of 4200 

 pounds. 



504. A wooden cantilever beam 3 feet long, 3 inches wide, and 

 4 inches deep has a load of 300 pounds at the free end, and is under 

 an axial compression of 4500 pounds. Determine the maximum com- 

 pressive unit-stress, neglecting weight of beam. 



505. A wooden cantilever beam 8 inches wide and 4 feet long 

 carries a total uniform load of 400 pounds per linear foot, and is sub- 

 jected to an axial compression of 40,000 pounds. Find the depth of 

 the beam so that the maximum compressive unit-stress shall be 1000 

 pounds per square inch. 



506. Solve Problem 501 for an axial tension of 60,000 pounds 

 instead of the axial compression. 



507. Find the size of a square, wooden simple beam of 12 feet 

 span to carry a load of 400 pounds at the middle, when it is also 

 subject to an axial tension of 3000 pounds, the maximum allowable 

 tensile stress being 1000 pounds per square inch. Neglect weight 

 of beam. 



