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प्रश्न
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.
उत्तर
Let the masses of the two resulting nuclei be represented as m1 and m2, and their velocities as v1 and v2 respectively. Thus, the total linear momentum after disintegration = m1v1 +m2 v2. Before disintegration, the nucleus is at rest. Therefore, its linear momentum before disintegration is zero.
According to the principle of conservation of linear momentum,
`m_1vecv_1 + m_2vecv_2 = 0 or vecv_2 = - (m_1vecv_1)/m_2`
The negative sign indicates that v1 and v2 point in opposite directions.
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