Con lắc lò xo gồm vật nặng m treo theo phương thẳng đứng. Trong quá trình dao động, khoảng cách giữa điểm cao nhất và điểm thấp nhất mà vật đi qua là 12 cm, tại VTCB lò xo dãn 4 cm. Lấy g = = 10 m/s2. Tốc độ cực đại của vật là

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