In a nuclear reaction carbon nucleus, 12c collides elastically in a head-on collision with an unknown nucleus. the initial speed of the carbon nucleus is 110 km/h and the speed of the unknown nucleus is 400km/h. after the collision the carbon nucleus moves in opposite direction to its original direction with a speed of 145km/h. i) determine the ratio of the mass of carbon nucleus and the unknown nucleus. ii) what is the velocity of the unknown nucleus after the collision?