Paper One : Q12

The mass of the Earth(M) and the gravitational field strength (g) at the surface are unknown quantities unless given in the question itself. You cannot refer to cover page and use g=9.81 ms-2. These 2 quantities are closely related. If M is given , g will not be given. If g is given , M will not be given. The relationship is GM = gR2.Take note that g is at the surface and not simply at any location!