NEET Sample Paper NEET Sample Test Paper-41

  • question_answer
    A machine which is 75% efficient, uses \[12\mathrm{J}\] of energy in lifting 1Kg mass through a certain distance. The mass is then allowed to fall through the same distance. The velocity at the energy of its fall is:

    A) \[\sqrt{12}\,m/s\]                       

    B) \[\sqrt{18}\,m/s\]

    C) \[\sqrt{24}\,m/s\]                       

    D) \[\sqrt{32}\,m/s\]

    Correct Answer: B

    Solution :

    \[\eta =\frac{{{E}_{o}}}{{{E}_{in}}}\] \[{{\operatorname{E}}_{o}}=\frac{75}{100}{{E}_{in}}=\frac{3}{4}\times 12=9\,\,Joule\] This \[{{\operatorname{E}}_{o}}\]get converted into K.E during fall by energy conbservation \[{{\operatorname{E}}_{o}}=\frac{1}{2}m{{v}^{2}}\] \[9=\frac{1}{2}\times 1{{v}^{2}}\] \[\operatorname{v}=\sqrt{18}\,\,m/s\]


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