4-1 할리데이 11판 솔루션 일반물리학

$$\begin{cases} v&=14.0\ut{m/s}\\ \vec a_1&=2.50\ut{m/s^2}\i \end{cases}$$ $$\begin{aligned} a &= \frac{v^2}{R}\\ 2.5&= \frac{14^2}{R}\\ \end{aligned}$$ $$\begin{aligned} R&=\frac{14^2}{2.5}\\ &=\frac{392}{5}\ut{m}\\ &=78.4\ut{m}\\ \end{aligned}$$ $$\ab{a}$$ $$\vec a = -\omega^2\vec x,$$ $$\begin{aligned} R_1&=78.4\ut{m}\\ \theta_1&=\pi\ut{rad} \end{aligned}$$ $$\ab{b}$$ $$\begin{aligned} R_2&=78.4\ut{m}\\ \theta_2&=\pi\ut{rad} \end{aligned}$$