Explanation: In human body the most complex organ is brain. Its weight is around 1.4 kilograms and this jelly- like mass of tissue contains about billions of nerve cells. It forms a million new connections within seconds and its strength and pattern keeps changing. So no two brain are same. Personalities, memories, habits are the result of these changing connections.
You can use the impulse momentum theorem and just subtract the two momenta. P1 - P2 = (16-1.2)(11.5e4)=1702000Ns If you first worked out the force and integrated it over time the result is the same