11-36 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} R&=0.250\ut{m}\\ v_i&=33.0\ut{m/s}\\ S&=225\ut{m}\\ v_f&=0\\ I&=0.155\ut{kg\cdot m^2}\\ \end{cases} $$ $$\ab{a}$$ $$2aS=v^2-{v_0}^2,$$ $$ \begin{aligned} a&=\abs{v^2-{v_0}^2\over2S}\\ &={121\over50}\ut{m/s^2}\\ &=2.42\ut{m/s^2} \end{aligned} $$ $$\ab{b}$$ $$\alpha={a\over R},$$ $$ \begin{aligned} \alpha&={121\over200}\ut{rad/s^2}\\ &=0.605\ut{rad/s^2}\\ \end{aligned} $$ $$\ab{c}$$ $$\tau_\net=I\alpha,$$ $$ \begin{aligned} \tau&=\frac{3751}{40000}\ut{N\cdot m}\\ &=9.3775\times10^{-2}\ut{N\cdot m}\\ &\approx 9.38\times10^{-2}\ut{N\cdot m}\\ \end{aligned} $$