\(p=mv=20.15=300\)
\(p_1=m_1v_1=8.26,5=212\)
\(p_2=\sqrt{p^2+p_1^2-2p_1p_2cos_{60}}=\sqrt{300^2+212^2-2.300.212.cos_{45}}=212,132\)
\(v_2=\frac{p_2}{m_2}=\frac{212,132}{20-8}=17,678\)
\(cos\alpha=\frac{p^2+p^2_2-p_1^2}{2pp_2}=\frac{300^2+212,132^2-212^2}{2.200.212,132}=0,7\)
\(\rightarrow\alpha=44,964\)