9th Class Science Gravitation and Floatation Question Bank Gravitation

  • question_answer
    The angular velocity of rotation of the earth in order to make the effective acceleration due to gravity equal to zero at equator should be

    A) \[\text{2}.\text{15 }\times \text{ 1}{{0}^{\text{3}}}\text{ rad}/\text{sec}\]

    B)        \[\text{2}.\text{25 }\times \text{ 1}{{0}^{-\text{3}}}\text{ rad}/\text{sec}\]

    C)  \[\text{1}.\text{25 }\times \text{ 1}{{0}^{\text{3}}}\text{ rad}/\text{sec}\]

    D)         \[\text{1}.\text{25 }\times \text{ 1}{{0}^{-\text{3}}}\text{ rad}/\text{sec}\]  

    Correct Answer: D

    Solution :

     We know,          \[g'=g-{{\omega }^{2}}R{{\cos }^{2}}\mu \] At equator,         \[\mu =0\]and\[b'=0\] \[\therefore \]  \[{{\omega }^{2}}=\sqrt{\frac{g}{R}}\] \[\Rightarrow \]               \[\omega =\sqrt{\frac{10}{6400\times 1000}}\]                    \[=\sqrt{\frac{1}{640000}}=\frac{1}{800}\]                    \[=\mathbf{1}\mathbf{.25\times 1}{{\mathbf{0}}^{\mathbf{-3}}}\mathbf{rad/sec}\]


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