The gravitational potential energy of two point masses is: E = _Gm1m2' T Where m1 and em are the two masses, G is the gravitational constant, and T is the distance between them. (i) State what the minus sign in this equatiOn tells us about the gravitational force. [1 mark] (ii) Calculate the gravitational potential energy of a 1.00kg mass at the earth's surface. [3 marks] (iii) Hence calculate the escape speed of the mass, i.e. the minimum speed at the surface necessary to escape from the earth's potential well. [5 marks]