10-23 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} \alpha&=2.00\ut{rad/s^2}\\ \Delta t_{1\rarr2}&=3.00\ut{s}\\ \Delta \theta_{1\rarr2} &= 90.0\ut{rad}\\ \end{cases} $$ $$\ab{a}$$ $$\Delta \theta=\omega_0t+\frac{1}{2}\alpha t^2,$$ $$ \begin{aligned} \omega_1&=\frac{\Delta \theta}{t}-\frac{\alpha t}{2}\\ &=27.0\ut{rad/s}\\ \end{aligned} $$ $$\ab{b}$$ $$\omega=\omega_0+\alpha t,$$ $$ \begin{aligned} \Delta t_{0\rarr1}&=\frac{\omega_1-\omega_0}{\alpha}\\ &=\frac{27}{2}\ut{s}\\ &=13.5\ut{s}\\ \end{aligned} $$