3-42 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} \vec d &=-1.5\ut{m}\j \end{cases} $$ $$\ab{a}$$ $$ \begin{aligned} \abs{6.0\vec d} &= \abs{-9\j}\\ &=9 \end{aligned} $$ $$\ab{b}$$ $$\text{South}$$ $$\ab{c}$$ $$ \begin{aligned} \abs{-2.0\vec d} &= \abs{3\j}\\ &=3 \end{aligned} $$ $$\ab{b}$$ $$\text{North}$$