9-34 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} h&=4.0\ut{m}\\ \Delta t&=1.5\ut{ms}=1.5\times10^{-3}\ut{s}\\ g&=9.80665\ut{m/s^2} \end{cases} $$ $$2aS=v^2-{v_0}^2,$$ $$ \begin{aligned} 2(-g)(-h)&=v^2-{0}^2\\ v&=\sqrt{2gh}\\ \end{aligned} $$ $$ \begin{aligned} \abs{F}&=\abs{\frac{\Delta \vec p}{\Delta t}}\\ \abs{s(mg)}&=\abs{\frac{m(\vec v_f-\vec v_i)}{\Delta t}}\\ smg&=\frac{m\sqrt{2gh}}{\Delta t}\\ \end{aligned} $$ $$ \begin{aligned} s&=\sqrt\frac{2h}{g}\frac{1}{\Delta t}\\ &=\frac{4}{3}\sqrt\frac{2}{g}\times10^{-3}\\ &\approx 602.1343410023834\\ &\approx 6.0\times10^2\\ \end{aligned} $$