\(\left|v\right|>\frac{\sqrt{3}}{2}v_{max}\Rightarrow\left[{}\begin{matrix}v>\frac{\sqrt{3}}{2}v_{max}\\v< -\frac{\sqrt{3}}{2}v_{max}\end{matrix}\right.\)
\(\Delta t=\frac{0,5}{4}=\frac{1}{8}\left(s\right)\) ;\(\Delta t=\frac{1}{\omega}arc\cos\left(\frac{\sqrt{3}}{2}\right)\Rightarrow\omega=\frac{4}{3}\pi\left(rad/s\right)\)
\(a_{max}=\omega^2A=\frac{160}{9}\pi^2\left(cm/s^2\right)\)
Tại thời điểm t=0, gia tốc của vật là: \(a=-\omega^2A\cos\frac{\pi}{3}=-\frac{160}{9}\pi^2.\frac{1}{2}\left(cm/s^2\right)\)
\(\Rightarrow a=-\frac{1}{2}a_{max}\)
\(\Rightarrow\Delta t_1=\frac{1}{\omega}arc\sin\left(\frac{1}{2}\right)=\frac{3}{4\pi}.\frac{\pi}{6}=\frac{1}{8}\left(s\right)\)
\(\Delta t_2=\frac{T}{4}=\frac{3}{2.4}=\frac{3}{8}\left(s\right)\)
\(\Rightarrow\Delta t=t_1+t_2=....\)
P/s: Check lại số má giùm em nha :)
