In the problem description is states that neutron is fired into a nucleus and knocks out a particle it collides with in a inelastic collision. The heavy nucleus essentially does not move in the collision. In the instance of the problem a neutron is fired in to a nitrogen nucleus with a velocity of 2.0x10^7 m/s. Two neutrons are detected coming out of the nucleus with angles of 30 degrees and 15 degrees. Determine the internal energy change of the nitrogen nucleus.