1. The problem statement, all variables and given/known data A stationary object is released from a point P at distance 4R from the centre of the earth which has radius R and mas M.What is the speed of the object when it hits the Earth's surfacehttps://scontent-kul1-1.xx.fbcdn.net/hphotos-xpt1/v/t34.0-12/11921921_10204785254702789_1979507807_n.jpg?oh=4a62967277ee876cb2de85befad6b89a&oe=55E68D61 2. Relevant equations Gravitational 3. The attempt at a solution By using the principle of conservational of energy. 1/2mv^2=-GMm/R-(-GMm/4R) which is the final point-initial point but the solution is 1/2mv^2=-GMm/4R-(-GMm/R) which is the initial point-final point So which 1 is correct i got little bit confused here.Arent we should use the final-initial to find the changes of gravitatinal potential energy?