4-33 할리데이 11판 솔루션 일반물리학

$$\begin{cases} A:\text{Ball}\\ B:\text{Floor}\\ C:\text{Elevator}\\ \end{cases}$$ $$\begin{cases} v_{0A\larr B}&=v_0=8.00\ut{m/s}\\ v_{C}&=2.00\ut{m/s}\\ g&=9.80665\ut{m/s^2}\\ \end{cases}$$ $$\ab{a}$$ $$\begin{aligned} 2aS&=v^2-{v_0}^2,\\ 2(-g)(H)&=(0)^2-{8}^2\\ \end{aligned}$$ $$\begin{aligned} H&=\frac{32}{g}\\ &\approx 3.263091881529371\ut{m}\\ &\approx 3.26\ut{m}\\ \end{aligned}$$ $$\ab{b}$$ $$\begin{aligned} 2aS&=v^2-{v_0}^2,\\ 2(-g)(H_B)&=(0)^2-{6}^2\\ \end{aligned}$$ $$\begin{aligned} H&=\frac{18}{g}\\ &\approx 1.835489183360271\ut{m}\\ &\approx 1.84\ut{m}\\ \end{aligned}$$ $$\ab{c}$$ $$\begin{aligned} a_{A\larr B}&=a_A-a_B=-g-0\\ &=-9.80665\ut{m/s^2} \end{aligned}$$ $$\ab{d}$$ $$\begin{aligned} a_{A\larr C}&=a_A-a_C=-g-0\\ &=-9.80665\ut{m/s^2} \end{aligned}$$