11-21 할리데이 11판 솔루션 일반물리학

$$\begin{cases} m&=0.500\ut{kg}\\ R&=9.00\ut{cm}=9.00\times10^{-2}\ut{m}\\ \theta&=30\degree\\ v_0&=0\\ v_1&=3.5\ut{m/s}\\ \end{cases}$$ $$v=v_0+at,$$ $$\begin{aligned} a&=\frac{v_1-v_0}{t}\\ &=\frac{7}{2}\ut{m/s^2}\\ \end{aligned}$$ $$\begin{cases} \Sigma F&=m a\\ \Sigma \tau&=I\alpha\\ a&=r\alpha\\ \end{cases}$$ $$\begin{cases} f-mg\sin\theta&=m (-a)\\ Rf&=I\alpha\\ a&=R\alpha\\ \end{cases}$$ $$\begin{aligned} I&=\(\frac{g\sin \theta}{a} -1\)m R^2 \\ &=\frac{81 (g-7)}{140000}\\ &=1.62385\times10^{-3}\ut{kg\cdot m^2}\\ &\approx 1.6\times10^{-3}\ut{kg\cdot m^2}\\ &\approx 1.6\ut{g\cdot m^2}\\ \end{aligned}$$