9-12 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} p_0&=8.0\ut{kg\cdot m/s}\\ p_1&=4.0\ut{kg\cdot m/s}\\ \end{cases} $$ $$ \begin{aligned} \vec p_0&=8\cos\theta\i+8\sin\theta\j\\ \vec p_1&=8\cos\theta\i=4\i \end{aligned} $$ $$ \begin{aligned} \theta&=\cos^{-1}\frac{4}{8}\\ &=\frac{\pi}{3}\ut{rad}\\ &\approx 1.0471975511965976\ut{rad}\\ &\approx 1.0\ut{rad}\\ \end{aligned} $$