a)Vận tốc: \(v_{max}=4cm/s\)
Chu kì: \(\dfrac{T}{2}=10s\Rightarrow T=20s\Rightarrow\omega=\dfrac{2\pi}{T}=\dfrac{\pi}{10}\)
Biên độ: \(A=\dfrac{v_{max}}{\omega}=\dfrac{4}{\dfrac{\pi}{10}}=\dfrac{40}{\pi}\left(cm\right)\)
b)\(\varphi=-\dfrac{\pi}{2}\)
PT vận tốc: \(v=4sin\left(\dfrac{\pi}{10}t-\dfrac{\pi}{2}\right)\)
PT gia tốc: \(a=4\cdot\dfrac{\pi}{10}\cdot cos\left(\dfrac{\pi}{10}t-\dfrac{\pi}{2}+\dfrac{\pi}{2}\right)=\dfrac{2\pi}{5}cos\left(\dfrac{\pi}{10}t\right)\)
em tự thay giá trị vào nhé