Question

A hunter on a frozen, essentially frictionless pond uses a rifle that shoots 4.20 g bullets at 965 m/s. The mass of the hunter (including his gun) is 72.5 kg, and the hunter holds tight to the gun after firing it. Find the recoil velocity of the hunter if he fires the rifle (a) horizontally and (b) at 56.0∘ above the horizontal.

Answer 1

Answer:

a) $V_H=0.056 (-i)m/s$

b) $V_H=0.031 (-i)m/s$

Explanation:

By conservation of the linear momentum:

$P_o = P_f$

$0 = M_H*V_H+m_b*V_b$

$V_H = m_b/M_H*V_b$

When the bullet is shot horizontally $V_b = 965m/s$

$V_H = -0.056m/s$

When the bullet is shot at 56.0° above the horizontal,

$V_b = 965*[cos(56),sin(56)]m/s=[539.62;800.02]m/s$

Since on the y-axis ground will absorb the shock, we only make the calculations on the x-axis:

$V_H = -0.031m/s$

$V_H = -0.056m/s$