6-58 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} v&=80.0\ut{km/h}=\frac{200}{9}\ut{m/s}\\ R&=350\ut{m}\\ m&=55.0\ut{kg}\\ \end{cases} $$ $$\ab{a}$$ $$ \begin{aligned} \Sigma F_R &= \frac{mv^2}{R}\\ &=\frac{44000}{567}\ut{N}\\ &\approx 77.60141093474427\ut{N}\\ &\approx 77.6\ut{N}\\ \end{aligned} $$ $$\ab{b}$$ $$ 90\degree $$