Question

A hunter on a frozen, essentially frictionless pond uses a rifle that shoots 4.20 gg bullets at 970 m/sm/s. The mass of the hunter (including his gun) is 69.5 kgkg, and the hunter holds tight to the gun after firing it. You may want to review (Page) . For related problemsolving tips and strategies, you may want to view a Video Tutor Solution of Collision along a straight line. Part A Find the recoil speed of the hunter if he fires the rifle horizontally.

Answer 1

Answer:

$0.059\ \text{m/s}$

Explanation:

$m_1$ = Mass of bullet = 4.2 g

$u_1$ = Initial velocity of bullet = 0

$m_2$ = Mass of hunter with rifle = 69.5 kg

$u_2$ = Initial velocity of hunter with rifle

$v_1$ = Final velocity of the bullet = 970 m/s

$v_2$ = Final velocity of the hunter with the rifle

As the momentum of the system is conserved we have

$m_1u_1+m_2u_2=m_1v_1+m_2v_2\\\Rightarrow v_2=\dfrac{m_1u_1+m_2u_2-m_1v_1}{m_2}\\\Rightarrow v_2=\dfrac{0-0-0.0042\times 970}{69.5}\\\Rightarrow v_2=-0.059\ \text{m/s}$

The recoil speed of the hunter is $0.059\ \text{m/s}$ in the opposite direction of the bullet.