xay ra tac hai đ ? Ngudi ta lam gi de khic phuc nhirng tie hai đ ?
Hoat đng cua hgc sinh
- Nguyen nhan la mdt luc nhd, nhung bién đi tuin hoan cd tan so bing tan sd dao đng rieng ciia h6 thi ed thi lam gay nhiing may mde thiei bi Idn rat chic chin.
- Khic phuc: khi che tao cac may mde, phai cd ging lam sao cho tan sd rieng cua mdi bd phan trong miy khic nhilu so vdi tin so bien đi cua cac luc cd thi tac dung len bd phan ay, hoac lam cho dao đng rieng tit nhanh. Khi lip dat may ciing phai tranh d l cho tin sd rung do may tao nen triing vdi tin so rieng ciia cac vat gin maỵ
Hoat dgng 5
Ciing cd bai hgc va dinh hudng nhiem vu hgc tap tiép theo
HS lam viec ea nhan, sau đ thao luan chung toan Idp.
Trg giiip cua giao vi§n
GV yeu cau HS dgc muc: "Em cd biét?" va cho bidt nguyen nhan lam gay cac cay ciụ
- HS lam cac bai tap trong phid'u hpc tap.
- HS vl nha lam bai tap 1, 2 SGK. - On lai each bieu diln mdt dao đng dilu hoa bing mdt vecta quaỵ
PHlfiu HOC TAP
Cau 1. Phit bilu nao sau day diing khi ndi vl ngoai luc tie dung len vat dao
đng dl dao đng cua nd trd thanh dao đng cudng biic ? Ạ ngoai luc tac dung len vat bién đi dieu hoa theo thdi gian. B. ngoai luc tic dung len vat ludn la hing sd.
C. ngoai luc tac dung len vat phu thudc vao thdi gian theo ham sd bac nhit. D. ngoai lire tic dung len vat phu thudc vao thdi gian theo ham so bac haị
Cau 2. Mdt vat chiu tic dung ciia mdt ngoai luc bien đi dilu hoa theo thdi gian 7^ = 7^0 cosQr. Khi đ, chuyen đng cua vat gdm hai giai doan la giai doan chuyen tiép va giai doan dn dinh. Dao đng cudng biirc cua vat la dao đng trong
Ạ giai doan chuyin tiép. B. giai đan dn dinh. C. ca hai giai doan.
D. nira diu ciia giai doan chuyen tiép. Cau 3. Khi hiSn tupng cdng hudng xay ra thi
Ạ tan sd gdc ciia ngoai luc bing tin sd gdc rieng cua he dao đng. B. tin sd gdc ciia ngoai luc gap 2 lin tin sd gdc rieng cua he dao đng. C. tin sd gdc ciia ngoai luc dat gia tri cue daị
D. tin sd gdc cua ngoai luc dat gii tri cue tilụ
Cau 4. Khi xuat hien hi6n tupng cdng hudng thi bien dp ciia dao đng cudng biic Ạ dat gia tri cue daị
B. dat gii tri cue tieụ
C. giam dot ngpt dén gii tri 0. D. khdng thay đị
Cau 5. Ket luan nao sau day diing khi ndi vl su phu thudc cua bien dp cua dao đng cudng biic vao luc can cua mdi trudng dao đng?
Khi hien tupng cdng hudng xay ra, biSn dp cua dao đng cudng biic Ạ cang Idn néu luc can cua mdi trudng dao đng cang bẹ
B. cang Idn neu luc can cua mdi trudng dao đng cang Idn. C. khdng phu thudc vao luc can cua mdi trudng dao đng.
D. chi dat gia tri cue dai khi luc can cua mdi trudng dao đng nhd khdng dang k l .
BAI12
T6NG HOP DAO D6NG
I - MUC TifiU
1. vi ki^n thiic