2. Questions Bank
  3. 9th Class
  4. Science
  5. Gravitation and Floatation

9th Class Science Gravitation and Floatation Question Bank Gravitation

  • question_answer
    Explorer 38, a radio-astronomy satellite of mass 200 kg circles the earth in an orbit of average 3R radius\[\frac{3R}{2}\] , where R is the radius of the earth. Assuming the gravitational pull on the mass of kg at the earth's surface to be 10 N, calculate the pull on the satellite.

    A)  889N  

    B)  8.89 N

    C)  8889N

    D)  88.9 N

    Correct Answer: A

    Solution :

     For earth,           \[g=\frac{GM}{{{R}^{2}}}\] For satellite,       \[g'=\frac{GM}{{{r}^{2}}}=\frac{g{{R}^{2}}}{{{r}^{2}}}=\frac{g{{R}^{2}}}{{{(3R/2)}^{2}}}\] \[\therefore \]  \[g'=\frac{4}{9}g\] \[\Rightarrow \]               \[g'=\frac{40}{9}N/kg\] \[\therefore \]Pull on the satellite,                 \[w=Bg'=200\times \frac{40}{9}=\mathbf{889}\,\,\mathbf{N}\]


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