Concept:An explosion is governed by internal forces. Therefore, the total momentum of the isolated system is perfectly conserved before and after the explosion.
Formula:$$ P_{initial} = P_{final} $$
$$ mv = m_1v_1 + m_2v_2 $$
Solution:- Total initial momentum: \( 6 \text{ kg} \times 4 \text{ m/s} = 24 \text{ kg m/s} \).
- After explosion, Piece 1 mass \( m_1 = 2 \text{ kg} \) and \( v_1 = 8 \text{ m/s} \). Its momentum = \( 2 \times 8 = 16 \text{ kg m/s} \).
- Piece 2 mass \( m_2 = \text{Total mass} - m_1 = 6 - 2 = 4 \text{ kg} \).
- Set up conservation: $$ 24 = 16 + 4v_2 $$
- $$ 8 = 4v_2 \implies v_2 = 2 \text{ m/s} $$ (Option A).
Why other options are incorrect:Failure to account for the remaining mass correctly, or adding momentums improperly, yields the values in Options B, C, and D.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.