4-2 할리데이 10판 솔루션 일반물리학

$$\begin{cases} p_x = -5.0\ut{m}\\ p_y = 8.0\ut{m}\\ p_z = 0.0\ut{m}\\ \end{cases} $$
(a)$\vec p=?$ $$ \vec p = (-5.0\ut{m})\i+8.0\ut{m}\j$$
(b)$p=?$ $$ \begin{aligned} p =& \sqrt{(-5)^2+8^2}\\ =& \sqrt{89}\\ \approx&9.4\ut{m} \end{aligned} $$
(c)$\phi_{p|\i}=?$ $$ \begin{aligned} \phi_{\vec p|\i}=&\cos^{-1}\(\frac{\vec p \cdot \i}{\abs{p}\abs{\i}}\)\\ =&\cos^{-1}\(\frac{-5}{\sqrt{89}}\)\\ \approx&2.1\ut{rad} \end{aligned} $$
(d)

(e)$\Delta\vec p=?$ $$ \vec p = (3.00\ut{m})\i$$
(f)$\Delta p=?$ $$p=3\ut{m}$$
(g)$\phi_{\Delta\vec p|\i}=?$ $$\phi_{\Delta\vec p|\i}=0$$