1. The problem statement, all variables and given/known data A rock is dropped from a distance RE above the surface of the Earth, and is observed to have a kinetic energy of K1, when it hits the ground. An identical rock is dropped from 2RE above the surface and has kinetic energy K2 when it hits the ground. Re is the radius of the earth. What is K2/K1. a) 2 b) 4/3 c) 3/2 d) 2/3 e)4 2. Relevant equations 3. The attempt at a solution K1= (-GMm)/(RE+ RE)= (−GMm)/2RE K2 = (-GMm)/(RE+ 2RE)= (−GMm)/3RE K2/K1 = [(−GMm)/3RE]/[(−GMm)/2RE] = [(−GMm)/3RE] * [(2RE/(−GMm)] = 2/3 = d). However the answer is 4/3, where did I go wrong?