Answer:
20,000 Ns
Explanation:
mass of exhaust gases, m = 50 kg
velocity of exhaust gases, v = 400 m/s
The momentum of a body is defined as the measurement of motion of body. mathematically, it is defined as the product of mass off the body an its velocity.
change in momentum of rocket = final momentum - initial momentum
                           =  m x v - 0
                           = 50 x 400
                           = 20,000 Ns
