Compute the acceleration of gravity for a given distance from the earth's center, distCenter, assigning the result to accelGravity. The expression for the acceleration of gravity is: (G * M) / (d2), where G is the gravitational constant 6.673 x 10-11, M is the mass of the earth 5.98 x 1024 (in kg) and d is the distance in meters from the earth's center (stored in variable distCenter).