Answer
We obtain $t_{2}$ using Eq. $10-15 :$
$$
\theta_{2}=\frac{1}{2}\left(\omega_{0}+\omega_{2}\right) t_{2} \Rightarrow t_{2}=\frac{2(40 \mathrm{rev})}{0.239 \mathrm{rev} / \mathrm{s}}=335 \mathrm{s}
$$
which we round off to $t_{2} \approx 3.4 \times 10^{2} \mathrm{s}$ .
Work Step by Step
We obtain $t_{2}$ using Eq. $10-15 :$
$$
\theta_{2}=\frac{1}{2}\left(\omega_{0}+\omega_{2}\right) t_{2} \Rightarrow t_{2}=\frac{2(40 \mathrm{rev})}{0.239 \mathrm{rev} / \mathrm{s}}=335 \mathrm{s}
$$
which we round off to $t_{2} \approx 3.4 \times 10^{2} \mathrm{s}$ .
