Railways NTPC (Technical Ability) Engineering Mechanics and Strength of Materials Question Bank Strength of Materials

  • question_answer
    A 10 cm long and 5 cm diameter steel rod fits snugly between two rigid walls 10 cm apart at room temperature. Young's modulus of elasticity and coefficient of linear expansion of steel are \[2\times {{10}^{6}}\,\text{kg/c}{{\text{m}}^{\text{2}}}\] and \[12\times {{10}^{-\,6}}\] per \[{}^\circ C\] respectively. The stress developed in rod due to a \[100{}^\circ C\] rise in temperature will be:

    A) \[6\times {{10}^{-\,10}}\,\text{kg/c}{{\text{m}}^{\text{2}}}\] 

    B) \[6\times {{10}^{-\,10}}\,\text{kg/c}{{\text{m}}^{\text{2}}}\]

    C) \[2.4\times {{10}^{3}}\,\text{kg/c}{{\text{m}}^{\text{2}}}\]   

    D) \[2.4\times {{10}^{4}}\,\text{kg/c}{{\text{m}}^{\text{2}}}\]

    Correct Answer: C

    Solution :

    \[{{\sigma }_{t}}=E\,\alpha .\Delta \theta \] \[=2\times {{10}^{6}}\times 12\times {{10}^{-6}}\times 100\] \[=2.4\times {{10}^{3}}\,\text{kg/c}{{\text{m}}^{\text{2}}}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner