Question
Thu March 19, 2015 By: Aryan Bawa

an iron rod 4m long and 0.5cm2 in cross section stretches 1mm when a mass of 225kg is hung from its lower end . calculate youngs modolus of iron?
 

Expert Reply
Yashvanti Jain
Thu March 19, 2015
begin mathsize 12px style Young apostrophe straight s space modolus comma space straight Y space equals bevelled fraction numerator space open parentheses straight F over straight A close parentheses over denominator open parentheses begin display style fraction numerator increment straight L over denominator straight L end fraction end style close parentheses end fraction open parentheses fraction numerator increment straight L over denominator straight L end fraction close parentheses space equals space fraction numerator 1 space cross times space 10 to the power of negative 3 end exponent space straight m over denominator 4 space straight m end fraction space equals space 0.25 space cross times space 10 to the power of negative 3 end exponent space straight m straight F space equals space 225 space kg space cross times space 9.8 space straight m divided by straight s squared space equals space 2205 space straight N Given space that space straight m space equals space 0.5 space cross times space 10 to the power of negative 4 end exponent space straight m squared Substituting space the space values space we space get colon straight Y space equals space bevelled fraction numerator space open parentheses fraction numerator space 2205 over denominator 0.5 space cross times space 10 to the power of negative 4 end exponent space straight m squared end fraction close parentheses over denominator open parentheses begin display style 0.25 space cross times space 10 to the power of negative 3 end exponent space straight m end style close parentheses end fraction space space space equals 1.76 space cross times 10 to the power of 11 space straight N divided by straight m squared end style
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