6-56 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} mg&=700\ut{N}\\ N_T&=540\ut{N}\\ \end{cases} $$ $$\ab{a}$$ $$ \begin{aligned} \text{light} \end{aligned} $$ $$\ab{b}$$ $$\Sigma F_R = \frac{mv^2}{R},$$ $$ \begin{cases} mg-N_T&= \frac{mv^2}{R}\\ N_B-mg&= \frac{mv^2}{R}\\ \end{cases} $$ $$ \begin{aligned} 0&=2mg-N_T-N_B\\ N_B&=2mg-N_T\\ &=860\ut{N} \end{aligned} $$ $$\ab{c}$$ $$ \begin{aligned} mg-N_{T}&= \frac{mv^2}{R}\\ N_T&=mg-\frac{mv^2}{R}\\ \end{aligned} $$ $$ \begin{aligned} N_{T2}&=mg-\frac{m(2v)^2}{R}\\ &=mg-4 \frac{mv^2}{R}\\ &=mg-4(mg-N_{T1})\\ &=60\ut{N}\\ \end{aligned} $$ $$\ab{d}$$ $$ \begin{aligned} N_B-mg&= \frac{mv^2}{R}\\ N_B&=mg+\frac{mv^2}{R}\\ \end{aligned} $$ $$ \begin{aligned} N_{B2}&=mg+\frac{m(2v)^2}{R}\\ &=mg+4 \frac{mv^2}{R}\\ &=mg+4(mg-N_{T1})\\ &=1340\ut{N}\\ \end{aligned} $$