(풀이자주 : 속력이 m단위라 임의로 m/s로 간주하여 풀었습니다.) $$\begin{cases} \theta_0 &= 30\degree\\ v_0 &= 25.0\ut{m/s}\\ d &= 20.0\ut{m}\\ \end{cases}$$ $$\begin{cases} \vec a &=-g\j\\ g &\approx 9.80665\ut{m/s^2}\\ \end{cases}$$ $$\begin{aligned} \Delta t_{0\rarr1} &= \frac{\Delta x_{0\rarr1}}{v_x}\\ &=\frac{d}{v_0\cos\theta}\\ &=\frac{8}{5 \sqrt{3}} \end{aligned}$$ (a) $h_1=?$ $$\Delta r = v_{0}t+\frac{1}{2}at^2,..