D. Phti thude ca ba yéu td neu tren.
PHAN HAI HifONG DflN Gini VfíDnP SO Chuang
DEN UCH DIEN TRLfClNG BAI 1 1.1 B. 1.2. D. 1.3. D. 1.4. D. 1.5. D. 2P
9 . 1 0 ^ ^ =mrco •co = 9.10^2ê = 1,41.10 ' rad/s 17
mr
^15!?£l = i,,4.10»N 1.6. a) 5,33.10 ' N 1.6. a) 5,33.10 ' N
b) F , = Fh, ^
r"
Lue háp đn qud nhd so vdi lue difn.
1.7. Difn tfch q ma ta truydn cho cae qua cdu se
phan bd đu cho hai qua cdụ Mdi qua edu mang mdt difn tfch —. Hai qua cau se day nhau
2
vdi mdt lue la F = k-~-. Vi gde gifla hai day „ treo a = 60 nen r = / = 10 cm. Mdi qua cdu se Hinh ỊIG
ndm can bang dudi tdc dting eua ba lite : sflc cang T ciia sgi day, lue difn F va trgng lue P ciia qua cdu (ffinh ỊIG).
Taco : tan— = — = F_
P
kq'
4l^mg ^ , = ±2/j^,a„f
q « ±3,58.10 ' C.
1.8. a) Trong trang thai can bang, nhiing lue difn tdc dung len mdi ion can bdng ldn nhaụ Didu đ ed nghia la tdt ca ede Itic phai ed eung mdt gia hay ba ion phai ndm tren cung mdt dudng ^->^
thang. Mat khae, hai ion am phai ndm đ'i Z ^^ xiing vdi nhau d hai ben ion dudng (Hinh ^ 1.2G), thi luc dien do ehung tac dung len ion Hinh 1.2G
duomg mdi cd the can bang nhaụ
b) Xet su can bdng eua mdt ion am. Cudng đ eua lue đy gifla hai ion
_4\q\e
1.9.
a_ 2
am : FA=k-— ; cua Itic hut gifla ion duong vd ion am F^=k-
a ã
Vi Fj = Fl,, nen \q\ = 4ẹ Kit qua laq = - 4ẹ
Xet su can bdng cua difn tfch q ndm tai dinh C chang han eua tam giac đu ABC, canh ạ Luc đy eua mdi difn tich q ndm d A hoac fl tdc dung
len difn tfch d C :
F=kC
Hgp luc eua hai luc đy cd phUdng ndm tren dudng phan giac eua gde C,
chidu hudmg ra, eudng đ :
2