As we know that here gun + bullet system is isolated from all other external force system
so here the momentum of system is always conserved
so we will say
[tex]m_1v_{1i} + m_2v_{2i} = m_1v_{1f} + m_2v_{2f}[/tex]
here we know that
[tex]v_{1i} = v_{2i} = 0[/tex]
[tex]m_1 = 10 kg[/tex]
[tex]m_2 = 0.001kg[/tex]
[tex]v_{1f} = 0.1 m/s[/tex]
now we will have
[tex] 0 + 0 = 10(0.1) + 0.001v_{2f}[/tex]
by solving above equation we will have
[tex]v_{2f} = 1000 m/s[/tex]
