d
(d)Initial momentum = \(mv\)
Final momentum = \((m + M)V\)
By conservation of momentum \(mv = (m + M)V\)
Velocity of (bag + bullet) system\(V = \frac{{mv}}{{M + m}}\)
Kinetic energy = \(\frac{1}{2}(m + M)\;{V^2}\)
=\(\frac{1}{2}(m + M){\left( {\frac{{mv}}{{M + m}}} \right)^2}\)\( = \frac{1}{2}\frac{{{m^2}{v^2}}}{{M + m}}\)
