A satellite is to be put into orbit 500 km above the earth's surface. If its vertical velocity (the velocity along the radius vector joining it to the earth's centre) is 2000 ms^–l at this height, the mass of satellite is 50 kg and radius of earth is 6400 km, the magnitude of the impulse required to put the satellite directly into the orbits (approximately) (assume g = 10 ms^–2)
(a) 4 × 10⁵ kg ms^–1              (b) 2 × 10⁵ kg ms^–1                  (c) 1.2 × 10⁵ kg ms^–1      (d) 3 × 10⁵ kg ms^–1