NEET-XII-Physics
11: Gravitation
- #24Find the acceleration due to gravity in a mine of depth 640 m if the value at the surface is 9.800 m s-2. The radius of the earth is 6400 km.Ans : Let g' be the acceleration due to gravity in a mine of depth d.
`` \therefore g\text{'}=g\left(1-\frac{d}{R}\right)``
`` =9.8\left(1-\frac{640}{640\times {10}^{3}}\right)``
`` =9.8\left(\frac{10000-1}{{10}^{4}}\right)``
`` =\frac{9.8}{{10}^{4}}\times 9999``
`` =9.8\times 0.9999``
`` =9.799\,\mathrm{\,m\,}/{\,\mathrm{\,s\,}}^{2}``
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