STRENGTH OF MATERIALS. 265 



To find the tensile strength. 



RULE. Multiply the area of the transverse section in 

 inches, by the weight given in the preceding table, and the 

 product will be the strength in Ibs. 



EXAMPLE. What is the tensile strength of a seasoned 

 white oak scantling 2 inches by 3 ? 



SOLUTION. 2x3=6, area of transverse section, x 13,600 

 = 81,600 Ibs. Ana. 



EXAMPLE SECOND. What is the tensile strength of a 

 round poplar stick 3 inches in diameter ? 



SOLUTION. 7.068, area of circle (vide table of the areas 

 of circles), x 7,000=49,476 Ibs. Ans. 



EXAMPLE THIRD. What is the tensile strength of the best 

 bar iron, 2 inches broad by 1 inch thick ? 



SOLUTION. 2x1=2, area of transverse section, x 72,000 

 =144,000 Ibs. Ans. 



NOTE. The above gives the 'maximum tensile strength of 

 the materials, or the utmost strain they are capable of sus- 

 taining when drawn lengthwise. But it is to be borne in 

 mind that the practical value is about one-fourth of the 

 above. 



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