Problem 7.121 Challenge

กำหนดให้ \(r = 0.350 m, ω_{0} = 0 rad/s, t = 10.0 s\) และ \(v = 11.0 m/s\)

จาก \(ω = ω_{0} + αt\)

\(\alpha =\frac{\omega  - \omega _{0}}{t}\)

\(\alpha =\frac{\frac{v}{r}- (0)}{t}\)

\(\alpha =\frac{v}{rt}\)

\(\alpha = 3.14 rad/s^{2}\)

กำหนดให้ \(ω_{0} = 0 rad/s, t = 20.0 s\) และ \(ω_{0} = 0 rad/s\)

จาก \(θ = ω_{0}t + \frac{1}{2}\alpha t^{2}\)

\(\theta =(0)(20.0)+\frac{1}{2}(3.14)(20.0)^{2}\)

\(\theta = 628 rad\)

จาก \(1\) รอบ \(= 2π rad\)

\(\therefore N =\frac{\theta}{2\pi}=\frac{628}{2\pi} = 100\) รอบ \(\;\blacksquare\)