Answer:
[tex]v_3 = 12 m/s[/tex]
Explanation:
As we know that during explosion of the object there is no external force on the system
So total momentum of the system will always remain conserved
so we will have
[tex]m_1 v_1 + m_2v_2 + m_3 v_3 = 0[/tex]
so here we can say
[tex]\vec v_3 = - \frac{(m_2 \vec v_2 + m_1 \vec v_1)}{m_3}[/tex]
so here we know that
[tex]m_1v_1 = m_2 v_2 = (7 )(4.3)[/tex]
[tex]m_1v_1 = 30.1 kg m/s[/tex]
now we know that
[tex]\vec v_3 = - \frac{2mv cos\frac{\theta}{2}}{m_3}[/tex]
[tex]\vec v_3 = - \frac{2(30.1)cos\frac{74}{2}}{4}[/tex]
[tex]v_3 = 12 m/s[/tex]