Question

Assuming earth to be a sphere of a uniform density, what is the value of gravitational acceleration in a mine 100 km below the earth's surface (Given R = 6400km)

• A.
• B. $7.64 m / s ^ { 2 }$
• C.
• D. $3.10 m / s ^ { 2 }$

Answer 1

Answer: (A)

Answer 2

Acceleration due to gravity at depth d, $= g \left[ 1 - \frac { 100 } { 6400 } \right]$ $= 9.8 \left[ 1 - \frac { 1 } { 64 } \right]$ $= 9.8 \times \frac { 63 } { 64 } = 9.66 \mathrm {~m} / \mathrm { s } ^ { 2 }$.