A nucleus moving with velocity `bar(v)` emits an `alpha`-particle. Let the velocities of the `alpha`-particle and the remaining nucleus be `bar(v)_(1)` and `bar(v)_(2)` and their masses be `m_(1)` and `(m_2)` then,

Options

A. `vec(v), vec(v)_(1)` and `vec(v)_(2)` must be parallel to each other.
B. None of the two of `vec(v), vec(v)_(1)` and `vec(v)_(2)` should be parallel to each other.
C. `vec(v)_(1)+vec(v)_(2)` must be parallel to `vec(v)`
D. `m_(1)vec(v)_(1)+m_(2)vec(v)_(2)` must be parallel to `vec(v)`

Answer

D