7. A rocket has a mass of 2 x 108 kg. It expels gas at the rate of 2 x 10t kg/s with an exhaust speed of 1000 m/s relative to the rocket. The initial acceleration of the rocket at the launch pad (neglect gravity) is closest to
(A) 1 m/s2,
(B)10m/s2,
(C)100 m/s2,
(D) 1000m/s2,
(E)100000 m/s2.
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