A rocket has an initial mass of 12,000 kg. After a vertical liftoff it burns fuel at the rate of 10 kg/s for 80 s until its fuel is exhausted. During this time a constant thrust of 220 kN is...

A rocket has an initial mass of 12,000 kg. After a vertical liftoff it burns fuel at the rate of 10 kg/s for 80 s until its fuel is exhausted. During this time a constant thrust of 220 kN is developed. Calculate the final velocity of the rocket. You may neglect air resistance.