T
toanmb


mot day dan hoi AB dai 2m, hai dau co dinh . khi co song dung voi tan so 20Hz, quan sat thay 2 bung song dao dong cung pha xa nhau nhat cach nhau 1,5m . toc do truyen song tren day la :
A20m/s B. 15m/s C. 25m/s D.10m/s
( cau 5 de 12 - thay hung)
giai ( sai o dau !?)
*d/k co song dung hai dau co dinh : AB = k.lamda/2 (1) ,k= 1,2,3......
* goi CD la 2 diem bung cung pha xa nhau nhat
* TH1 : ( so bung la le) thi AB - CD = lamda/2 = 0,5m => lamda = 1m =>. v= 20 m/s
* TH2 : so bung la chan thi AB - CD = 4.lamda/4 = 0,5 => lamda = 0,5m =>. v= 10 m/s
nho moi nguoi xem giup nhe !
A20m/s B. 15m/s C. 25m/s D.10m/s
( cau 5 de 12 - thay hung)
giai ( sai o dau !?)
*d/k co song dung hai dau co dinh : AB = k.lamda/2 (1) ,k= 1,2,3......
* goi CD la 2 diem bung cung pha xa nhau nhat
* TH1 : ( so bung la le) thi AB - CD = lamda/2 = 0,5m => lamda = 1m =>. v= 20 m/s
* TH2 : so bung la chan thi AB - CD = 4.lamda/4 = 0,5 => lamda = 0,5m =>. v= 10 m/s
nho moi nguoi xem giup nhe !
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