T
tuyen05081995


hai nguon ket hop tren mat thoang cua chat long dao dong theo phuong trinh U1=U2=4cos10pit(mm).coi bien do song khong doi ,toc do truyen song v=15cm/s. hai diem M1 va M2 cung nam tren 1 elip nhan A,B lam tieu diem co AM1-BM1=1cm,AM2-BM2=3,5cm.Tai thoi diem li do cua M1 la 3mm thi li do cua M2 bang bao nhieu