A rocket has a mass of 1200 kg, including 1000 kg of fuel, which is consumed at a rate of 12.5…

A rocket has a mass of 1200 kg, including 1000 kg of fuel, which is consumed at a rate of 12.5 kg/s and ejected with a relative velocity of 4000 m/s. Knowing that the rocket is fired vertically from the ground, determine its acceleration (a) as it is fired, (b) as the last particle of fuel is being consumed.