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hoamamcute
2 năm trước
một vật có dao động điểu hòa với chu kỳ T = $\pi$ (s) và biên độ là 3cm. Li độ dao động là hàm sin gốc thời gian chọn vào lúc li độ cực đại .Phương trình vận tốc của vật theo tg có dạng là A. v=6cos(2t + $\pi$/2)cm/s B. v=6cos($\pi$t ) C. v=6$\pi$cos(2t + $\pi$/2)cm/s D. v=6$\pi$sin(2 $\pi$t )
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