A nucleus is at rest in the laboratory frame of reference. Show that if it disintegrates into two smaller nuclei, the products must move in opposite directions.
Let m masses of the parent nucleus and m1 and m2 be the respective two daughter nuclei. The parent nucleus is at rest.Initial momentum of the system (parent nucleus) = 0 Let v1 and v2 be the respective velocities of the daughter nuclei having masses m1 and m2. According to the law of conservation of momentum: Total initial momentum = Total final momentum 0=m1v1+m2v2 v1=m1−m2v2 Here, the negative sign indicates that the fragments of the parent nucleus move in directions opposite to each other.
