Answer:
[tex]0.059\ \text{m/s}[/tex]
Explanation:
[tex]m_1[/tex] = Mass of bullet = 4.2 g
[tex]u_1[/tex] = Initial velocity of bullet = 0
[tex]m_2[/tex] = Mass of hunter with rifle = 69.5 kg
[tex]u_2[/tex] = Initial velocity of hunter with rifle
[tex]v_1[/tex] = Final velocity of the bullet = 970 m/s
[tex]v_2[/tex] = Final velocity of the hunter with the rifle
As the momentum of the system is conserved we have
[tex]m_1u_1+m_2u_2=m_1v_1+m_2v_2\\\Rightarrow v_2=\dfrac{m_1u_1+m_2u_2-m_1v_1}{m_2}\\\Rightarrow v_2=\dfrac{0-0-0.0042\times 970}{69.5}\\\Rightarrow v_2=-0.059\ \text{m/s}[/tex]
The recoil speed of the hunter is [tex]0.059\ \text{m/s}[/tex] in the opposite direction of the bullet.