Ta có: \(v_1 = v_{max}.cos\alpha = 2 \pi cm/s\)
\(v_2 = v_{max}.cos\beta = - 2\sqrt{3} \pi cm/s\)
Lại có: \(\beta - \alpha = \frac{\pi}{2}\)
\(\Rightarrow v_2 = v_{max}.cos\beta = - v_{max}.sina\)
\(\Rightarrow \frac{v_1}{v_2} = \frac{v_{max}.cos\alpha }{-v_{max}.sin\alpha }\Leftrightarrow \frac{2 \pi}{-2 \sqrt{3} \pi} = - cot \alpha \Rightarrow \alpha = \frac{\pi}{3}\Rightarrow v_{max} = 4 \pi cm/s\)\(\Rightarrow w = \frac{v_{max}}{A} = 2 \pi rad/s \Rightarrow f = 1H_Z\)
=> Đáp án C
