Aspaceship which is 50,000 kilometers from the center of earth has a mass of 3,000 kilograms. what is the magnitude of the force of gravity acting on the spaceship? (the value of g is 6.673 × 10-11 newton meter2/kilogram2. the mass of earth is 5.98 × 1024 kilograms.)

a.400 newtons
b.478 newtons
c.500 newtons
d.1595 newtons