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

  • question_answer
    A short column of external diameter D and internal diameter d carries an eccentric load d. The greatest eccentricity which the load can have without producing tension on the cross-section of the column would be

    A) \[\frac{d+D}{8}\]                     

    B) \[\frac{{{d}^{2}}+{{D}^{2}}}{8d}\]

    C) \[\frac{{{d}^{2}}+{{D}^{2}}}{8D}\]            

    D) \[\sqrt{\frac{{{d}^{2}}+{{D}^{2}}}{8}}\]

    Correct Answer: B

    Solution :

    Tensile stress \[=-\frac{P}{A}+\frac{Pe}{l}+\frac{D}{2}=0\] \[\therefore \,\,\,\frac{1}{A}=\frac{eD}{2l}\] \[\frac{4}{\pi ({{D}^{2}}-{{d}^{2}})}=\frac{eD\times 64}{2\times \pi ({{D}^{4}}-{{d}^{4}})}\] \[e=\frac{8\pi ({{D}^{4}}-{{d}^{4}})}{64\times \pi \times D({{D}^{2}}-{{d}^{2}})}\] \[=\frac{{{D}^{2}}+{{d}^{2}}}{8D}\]


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