2. Questions Bank
  3. 9th Class
  4. Science
  5. Work and energy

9th Class Science Work and energy Question Bank Work, Energy and Power

  • question_answer
    A body of mass \[0.5\,\,kg\] is taken to a height \[{{R}_{e}}\]above the earth's surface, where \[{{R}_{e}}\] is the radius of the earth. If the body is now raised through a height of\[2\,\,m\], what is the increase in its potential energy?

    A) \[0.25\,\,J\]         

    B)        \[0.50\,\,J\]

    C) \[0.75\,\,J\]       

    D)        \[1.25\,\,J\]

    Correct Answer: A

    Solution :

     \[g'=g{{\left( \frac{{{R}_{e}}}{{{R}_{e}}+{{R}_{e}}} \right)}^{2}}=\frac{g}{4}=0.25\,\,m\,\,{{s}^{-2}}\] \[\therefore \]Increase in\[P.E.=mg'h\] \[=0.5\times 0.25\times 2=0.25\,\,J\]


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