1. The problem statement, all variables and given/known data A planet of radius R = (radius of earth)/10 has the same mass density as earth. Scientists dig a well of depth R/5 on it and lower a wire of the same length and of linear mass density 10-3 kgm-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 x 106m and the acceleration due to gravity on earth is 10 ms-2 ) 96 108 120 150 2. Relevant equations I think there is some formula for gravitational acceleration when we dig a depth on planet. Don't know that or the derivation. 3. The attempt at a solution Density = mass/volume Volume = 4/3πR3 I do not know what is happening by digging.