9-31 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} m&=0.15\ut{kg}\\ v_i&=5.00\i+6.50\j+4.00\k\ut{m/s}\\ v_f&=2.00\i+3.50\j-3.20\k\ut{m/s}\\ \end{cases} $$ $$\ab{a}$$ $$ \begin{aligned} \Delta \vec p&=\Delta (m\vec v)\\ &=m\Delta \vec v\\ &=-\frac{9}{20}\i-\frac{9}{20}\j-\frac{27}{25}\k\ut{kg\cdot m/s}\\ &=-0.45\i-0.45\j-1.08\k\ut{kg\cdot m/s}\\ &\approx -0.45\i-0.45\j-1.1\k\ut{kg\cdot m/s}\\ \end{aligned} $$ $$\ab{b}$$ $$ \begin{aligned} \vec J_A&=\Delta \vec p\\ &=-0.45\i-0.45\j-1.08\k\ut{N\cdot s}\\ &\approx -0.45\i-0.45\j-1.1\k\ut{N\cdot s}\\ \end{aligned} $$ $$\ab{c}$$ $$ \begin{aligned} \vec J_B&=\vec J_A\\ &=-0.45\i-0.45\j-1.08\k\ut{N\cdot s}\\ &\approx -0.45\i-0.45\j-1.1\k\ut{N\cdot s}\\ \end{aligned} $$