6-45 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} R&=200\ut{m}\\ g&=9.80665\ut{m/s^2} \end{cases} $$ $$\Sigma F_R = \frac{mv^2}{R},$$ $$ \begin{aligned} \frac{mv^2}{R}&=mg\\ v&=\sqrt{gR}\\ &\approx 44.28690551393267\ut{m/s}\\ &\approx 4\times10\ut{m/s}\\ \end{aligned} $$