EAMCET Medical EAMCET Medical Solved Paper-1997

  • question_answer
    The mass of a planet is 1/9 of the mass of the earth and its radius is half that of the earth. If a body weights 9 N on the earth, its weight on the planet would be:

    A)  6 N                                       

    B)  4 N

    C)  2.25 N                                 

    D)  I N

    Correct Answer: B

    Solution :

                     Weight of the object of mass m on earth \[{{W}_{e}}=m{{g}_{e}}=\frac{G{{M}_{e}}m}{R_{e}^{2}}\]                                           ?(i) Weight of object of mass m on planet \[{{W}_{p}}=m{{g}_{p}}=\frac{G{{M}_{p}}m}{R_{p}^{2}}\]                           ?(ii) From Eqs. (i) and (ii) \[\frac{{{W}_{p}}}{{{W}_{e}}}=\frac{G{{M}_{p}}m}{r_{p}^{2}}\times \frac{R_{e}^{2}}{G{{M}_{e}}m}\] \[=\frac{{{M}_{p}}}{{{M}_{e}}}{{\left( \frac{{{R}_{e}}}{{{R}_{p}}} \right)}^{2}}\]                                 ?(iii) \[\left( \begin{align}   & \text{Given: }{{M}_{p}}=\frac{1}{9}{{m}_{e}} \\  & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{{r}_{p}}=\frac{1}{2}{{R}_{e}} \\  & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{{W}_{e}}=9N \\ \end{align} \right)\] \[\frac{{{W}_{p}}}{{{W}_{e}}}=\frac{\frac{1}{9}{{M}_{e}}}{{{M}_{e}}}\times {{\left( \frac{{{R}_{e}}}{1/2{{R}_{e}}} \right)}^{2}}\] \[{{W}_{p}}=\frac{4}{9}\times 9=4N\]


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