... = 3mg (3cosa -2cosao o B) V(a) = 2 gl (cos cos ), Q(x) =2 mg (3cosa -2cosao C) V(a) = D) V(a) = gl (cos cos ), Q(x) = mg (3cosa -2cosa o o gl (cos cos ), Q(x) = 0,1mg (3cosa -2cosao o 2 ... phng trỡnh dao ng ca hai dao ng ó cho A) x1 = 2cos t (cm), x2 = cos t (cm) B) x1 = cos t (cm), x2 = - cos t (cm) C) x1 = -2cos t (cm), x2 = cos t (cm) D) x1 = 2cos t (cm), x2 = cos t (cm) ... có dạng: A v2 = gl.cos(0 - ) B v2 = 2gl.cos(0 - ) C v2 = gl.[cos() - cos(0)] D v2 = 2gl.[cos( ) - cos 0] Câu 81 Mt lc n gm mt dây treo di 1,2m, mang mt vt nng lng m = 0,2 kg, dao ng ni gia tc...