1.
A planet of radius R=10×R = 10 \times (radius of Earth) has the same mass density as Earth. Scientists dig a well of depth R/5R/5 on it and lower a wire of the same length and of linear mass density 10−310^{-3} kg m−1^{-1} into it. If the wire is not touching anywhere, the force applied at the top of the wire by a person holding it in place is (take the radius of Earth =6×106= 6 \times 10^6 m and the acceleration due to gravity of Earth =10= 10 m s−2^{-2}):
Gravitation - Very Hard - Question