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r

m

m

m

ng cao

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due
Giao
Viet Nam.
01-2010/CXB/639-1485/GD

Ma s6': NB006T0


Ldi MOI BAIJ=
Cac em hoc sinh than Imen

Cuon Bai tap Vat10ll
nang cao la
mgt bo phanhihi
cO
cOa sach giao khoa
Vatli10 nang cao,no se giup cac
hoc tot han mon Vat ll. Sach duac chia
lam
phan,
mdi hai
umg vdi cac
cht/ang cCia
sach

phan g6m cac chuang tuang
giao khoaVatli10 nang cao.
Phan motgom cac bai
tapvi du
va debai.
Cac baitapvidu
la nhumg baitap.di^n
hinh trong cac chuang nen
trinh bay tiet.
chi Cac em co the tim phuang
thay phap giai
chung cho cac bai tap trong chuang do.

Cac em hay co
Phan hai la cac hudng dan giai.
va ldi
gang tim each
giai cac bai tap, dUng voi doc ph
Hay xem lai bai hoc mdi khi chua
ducfctim
each
giai mot
Ch!khi nao thuc su khdng
dUdc
timeach
bai tap nao dd.
giaicac em mdi
xem hudng din hoac
ldi
giai.

Cudi mol chuang cd cac bai tap ve thi nghiem
chung ta. Hay thu
gan gui vdl ddi song hangcQa
ngay
hien cac thi nghiem trinh bay d day. Cac so l
cOa chinh cac em cung se
nhumg
la bai tap hay.
Chuc cac em hoc gioi va ngay cang yeu thich
Vatli.

Cac tac gia



DEBAI

Phan mot
DONG HOC

CHAT DI M

I - BAI TAP VI DU
Ba! 1
M6t cha^t
dilm chuyin
d6ng’tr6n m6t dvrofag
thang. D6 thi chuyin
d6ngcua no

duac ve tr6n Hinh LL
1. Hay m6 ta chuyin ddng
chSft
dilm.
cua

2. Tinh van tdc
trungbinhva tdc
d6 trung binh chft
cuadilm trong c
: 0sau
s-^ls;0s-^4s;ls-^5s;0s-^5s.
khoang thoi gian
x(cm)M

Hinh 1.1

Bdi gidi

1. Trong khoang thod gian tur
dintt == s,
1
0d6s thi chuyin ddng
m6t l
dudng thang I6n
diva lam mdt aj
gocv6itrueOt. Nhu
vay ch^t
dilmchuyin
ddng thing

diutheo chilu duong
true
cua
toa dd,
tut
vitri
cd toa dd bang
dinvi
0
tried toa dd bang 4 cm. Van
ch&tdc
dilm
cua
bang :
4
V = tanttj = = 4 cm/s


TiJfluc t = din
1 s
t = 2,5 s, dd thi
duorng
lathang
mdt di xudng va la
Ot. Nhu vay
chatdilmchuyin
ddngdiutheo ehilu
nguoelai,
tctc
goc a2 vdi true

la theo chieu
am cuatrue
toa dd, tur vi tri x = 4 cm den vi tri
: la
.
cua chat dilm
-2-4
, ,
V = tana-=
= - 4 cm/s
-

2

1,5

.

’

’

.

.

liic
t = 4d6
s,
thi la mdt dudng nam ngang song

Txt luc =t2,5 s den
true thdi gian, chat diem
diing
d vi
tri yen
cd toa do x = - 2 cm.

Tu: liic
t= 4 sdint= 5 s, dd thi la mdt dudng thang di ldn
a3 v
vdi true
Ot. Nhu vay chat dilm chuyin ddng thangduofng
deu eua
theotru
c
toa do
tit
vi tri
X = -2 em den vi tri x = 0 em. eh^t
Vandilm
tde la
eua:
0 - (-2)^
,
= 2 cm/s
V = tana ,=
1

’

.

.

.

,

’

.

2. Van tde trung binh
tinh
duoc
theo edng thiic :
Vtb

=

dd ddi
X,
khoang
thdi
gian X9 t2
tj
.
’
^
^

,
.

Tdc dd trung binhtinh
dugc
theo cdng thtic :
T^-’ -»->. u-u quang dudng di duoc
Toe do tmng
binh=
S;
khoang thdi gian
thi
= 0 om ; t2
luc
= 1 s thi
X2 = 4 cm, hay la
a) Luctj= 0 s Xj
At =t2- tl= 1 s -= 10 s
Dd ddi trong khoang thdi :gian dd la
Ax = X2 - X]= 4 - 0 = 4 cm
Vay :
^tb= ^ = Y ^ "^
’^"^Z^Quang dudng dugfc
di trong khoang thdi gian dd la :
As = |x2- XJI = 4 0.
- = 4 cm
vay :

As

Tdc dd trung binh =

= 4 cm/s.

b) Liic =tj0 s Xj
thi
= 0 em ; t2
luc
= 4 s X2
thi
= - 2 cm.
At = t 2 - t4i - =0= 4 s


Ax ==X2 vay:

Vtb

Xj=

- 2-0
- =-2 cm

_
_ ^^ -2
_
-0,5cm/s.
~ At ~ 4

Do chuyin ddng khdng theo mdt ehilu eho nen ta tmh

dugc
quang
nhu sau:
s
tj
= 1 s, quang dudng di Asi
dugc
= |x2
la- x11 = |4 - 0| = 4
Tilf =
tl0 din
Tuf t’l
= 1 s den
tj= 2 s, quang dudng diAs2
dugc
=|0 la
- 4| = 4 em.
t’{
= Tii
2 s
din t’l"
= 2,5 s, quang dudng di
AS3duge
= 1-2la
- 0| = 2 cm.
tj"Ttr
- 2,5din
s
t2 = 4 s,
chatdilm diing lai d =dilm

- 2 cm,
x quang dudng di AS4
dugc
- 0.
la
vay quang dudng di dugc trong khoang ti
thdi
0= sgian
den
t2=tuf
4 s la :
As = Asi+ As2+ AS3 =4 + 4 2+= 10 cm
Tdc dd trung binh trong khoang thdi gian dd la :
Tdc dd trung binh = -- = =2,5 cm/s
At
4

Ta nhanthaygia tri van
eua
tdc trung binh va tdc dd trung binh tr
khoang thdi gian dd la khae nhau.
c) Tuong tu, trong khoang thdi
t2-gian
ti= 5 At
- =1 = 4 s,
. ta ed
Ax = X2 - Xi =0 - =4- 4 cm
’ 4
,
.

Ax
^^^ = AT = -4 = "^’^"^/^
As = As2+ AS3 + AS4 + AS5 = 4 + 2 + 0 + 2 = 8 cm
As
8
Tdc dd trung binh
-: ==-r= 2 cm/s
At
4
d) Trong khoang thdi gian
At
t2- ti
= 5= - 0 = 5 s, ta cd :
Ax = X2 - Xl = 0 - 0 = 0 cm
Vtb = T = 0 c"^/s
As = Asi+ As2+ AS3 + AS4 + Asg= 4 + 4 + 2 + 0 + 2 =
A

10

Tdc dd trung binh
= - = - =2,4 em/s
At
5


Bai 2

Mdt xe nho trugt trdn mang nghidng
Oign

ddm
truekhf.
toa dd Ox tri
mang va cd ehilu duong hudng
xudng
phia
dudi. Biet rang, gia tdc cua
la 8 cm/s
,vaWe xe di ngang qua gdcvan
toa
tdcdd,
cua nd
VQ =
la- cm/Si
6

1. Vilt phuong tnnh chuyin ddng
l^ygdc
cua thdi
xe, gian
liic
xe
la di ngan
qua gdc toa
dd.
2. Hdi xe chuyin ddng theo hudng nao, sau bao lau thi
xe nam d vi tri nao ?

3. Sau dd xe chuyin ddng nhu thetinh
nao van

?tdc
Haycua xe sau 3 s
luc diing Liic
lai.
dd xe nam d vi tri nao ?
Bdi gidi

1. Phuong trinh chuyin
evia
ddng
xe la phuong tnnh chuyin ddng
ddi diuvdi van tdc ban
VQ =ddu
- 6 em/s, gia tdc bang 8 em/s va
XQ = 0 em. Phuang trinh dd la :

X = - 6.t .8.t^
+ (1)
2
2. a) Xe chuyin ddng phia
di trdn
ldn theo ehilu
am cua true Ox va dii
khi van tde bang khdng. Ta cd :
v = Vo+ at = - 6 + 8.t = 0
(2)
Tut ddsuyra:
8.t = 6 , hay

t = -

= 0,75 s

o

b) Vi tri cua xe luc
:
do la

X = - 6 . 0,75
.8.(0,75)^
+ - = - 2,25 em
>
2
3. a) Sau khi dat van tde bang 0 thi xe chuyin
ddn diu
theo
ddng chil
nha
ngugc lai xudng
phiadudi (chilu duong eiia true Ox).
xe diing
b) van tde eua xe dugc tmh theo edng thiieWc(2).
Sau 3l
tlie la d thdi dilm t = 0,75 + 3 = 3,75
s, bang
van tdc
cua xe
liic
dd

:
v =VQ + at = - 8.3,75
6 + = 24 cm/s
c) Liic
dd vi tri ciia
: xe la
X = - 6 .3,75 ^+.8.(3,75)2 = 33,75 cm


n - D^ BAI

L l . Trong mdt ldn
thtt
xe d td, ngudi ta xac dinh duge vi tri c
dilm each nhau ciing mdt khoang
1 sthdi
(xemgian
bang dudi day).
Hay xac dinh van tdc trung binh cua d td :
a) Trong giay ddu tidn.
b) Trong 3 gidy cudi ciing.
e) Trong sudt thdi gian quan sat.
x(m)

0

2,3

9,2

20,7

36,8

57,5

t(s)

0

1,0

2,0

3,0

4,0

5,0

1.2. Mdt ngudithi
tap
due chay trdn mdt dudng thang. Luc
dd chay
ddu n
vdi vdn tdc trung binh 5 m/s trong thdi gian 4 min. S
van tdc cdn 4 m/s trong thdi gian 3 min.
a) Hdi ngudi dd chay dugc quang dudng bang bao nhidu ?
trong
bd thdi gian chay bang bao nhieu

b) vantdc trung binhtoari
1.3. Mdt ngudi
beddgc theo chilu
xudt phat trong 42 s. Hay
a) Trong ldn boi ddu ti6n
b) Trong ldn boi vl.
c) Trong sudt quang dudng

dai 50 m hit
ciia
40 s,
bl rdi
boi quay lai
xdc dinh van tdc trung binh v
theo chilu dai cua bl bod.
di va vl.

1.4. Hai d td ciing xud’t phat tur Ha thii
Ndi di
nhat
chay
Vinh,
vdichile
van t
60 km/h, chile
thii
hai chay vdi van tdc trung binh 7
trung binh
1 h 30 min chile
thii

hai dufng lai nghi 30 min rdi tilp
vantdc
tuc
nhu trude. Coi cac d td chuyin
ddng
tr6n
mdt dudng thang.
a) Bilu diln dd thi chuyin ddng cua hai
h6xe
true
tren
toacung
dd. m
b) Hdi sau bao lauthii
thi
hai xe
dudi kip xe ddu ?
?
c) Khi dd hai xe each Ha Ndi
bao xa

1.5. Dd thi chuyin ddngngitdi
cuadimdt
bd va mdt ngudi di xe dap
1.2!
diln nhu Hinh
a) Hay lap phuang trinh chuyin
tumgddng
ngudi.
cua

b) Duatr6n
dd thi, xac dinh vi tri va thdi dilm hai ngudi

c) Tur cdc phuang trinh chuyin ddng da thanh ldp thdi’
d cdu
dilm hai ngudi gap nhau. So
kit
sanh
qua tim
cac dugc d cdu a va b.


Hinh 1.2

1.6.

Lue 6 h, mdt doan
turThanh
tau phd Hd
ChiMinh di Nha Trang vdi
45 km/h. Sau khi chay dugc 40 min thi tau dumg lai d
Sau dd lai tilp tuc chay vdi van td’e
Liic6bdng
h 50lue
min,
ddu.
mdt
td
khdi hanh
txtThanh phd Hd Chi Minh di

Trang
Nha vdi
vdn td’e 60 k
Coi chuyin ddng cua tau va ddiu.
td la thang
a) Ve d6 thi chuyin ddng cua tau
trfin
va
ciing
ciiamdt
d true
td
hdtoa dd,
b) Cancii
vao dd thi, xac dinh vi tri va thdi gian d td
e) Lap phuang trinh chuyin ddng cua tau va eiia d td
quatau.
tim So
dugc
6s
chay va tim vi tri, thdi dilm d td dudikit
kip
cdu a va b.

1.7.

Luc 7 h, mdt d td chay tii Hai Phdng
vanvl
tdc Ha60 Ndi
km/

Ciing luc, mdt d td chay tur Ha Ndi di Hai Phdng vdi
Hai Phdng each Ha105
Ndi
km va coi chuyin ddng la thang.

a) Lap phuang trinh chuyin ddngtrfin
eua
haimdt
xe true toa
cung
gd’c tai Ha Ndi va chilu duang la ehilu tur Ha Ndi d
7 h lam gdc thdi gian.
b) Tinhvi tri va thdi dilm hai xe gap nhau.
c) Ve dd thi hai
xe
ti&n
ciing
mdt hinh. Dura vao dd thi, xae d
quatinh
duge d cau b.
dilm hai xe gap nhau. Sokit
sanh
vdi
1.8.

10

Mdt d td chay trdn mdt dudng
vantdc
thang

25 vdi
m/s. Hai gidy
td’e eiia xe la 20 m/s. Hdi giaciia
tdc
xe trung
trong binh
khoang thd
dd bang bao nhidu ?


1.9.

Mdt chdt dilm chuyin
trfen
mdt
ddng
dudng thang.
Liic
t = 0, van td’e c
s,td’e eua nd
21m/s.
la Hdi:
la 5 m/sliic
;t.= 4van
a) Gia tdc trung binh cua
khoang
nd thdi
tronggian dd bang bao nhie
b) Ta edthi tinh
dugcvantd’e trung binh ciia nd trong khoang

dugc khdng ? Giai thich.
nhd eae sd tr6n
lidu

1.10. Mdt
electron
chuyin ddng trong dng den hinh eua mdt may
tang td’e
diudan tur
vantdc3.10m/sdinvan tdc 5.10 m/s trtn md
tinh
dudng thang bang 2 cm.
Hay:
a) Gia tdc dlectron
cua trong chuyin ddng dd.
Electron
dihitquang dudng dd.
b) Thdi gian

~1.11.Mdt d td chay
diutr6n dudng thang vdi van td’e 30 m/s vugt
phep va bi canh sat giao thdng phat hien. Chi sau 1 s
mdt eanh sat, anh nay phdng xe dudi theo vdi gia tde kh
a) Hdi sau bao lau thi anh eanh sat dudi kip d td ?
b) Quang dudng anh di dugc la bao nhidu ?

thuytang tdc
diudan tii 15din
m/s
27 m/s tren mdt quang d

1.12. Mdt tau
thang dai 70 m. Hay xac dinh :
d) Gia tdc eiia tau.
b) Thdi gian tau chay.

1.13. Mdt d td trSn
chay
mdt con dudng thang vdi van tdc khdng doi
Sau mdt gid, mdt d td khac dudi theo voi tir
van
td’e dilm
khdn
ciing
xudt phat va dudi kip
d tdsau quang dudng 200 km.
thu"nhdt
a) Tinhvdn tde euathii
d hai.
td
b) Giai bai toan bang dd thi.
1.14. Mdt vdt chuyin ddng thang cd van tdc la 5,2 m/s. Hd
2,5 s bang bao nhi6u, nlu :
a) Gia tdc cua nd bang 3 m/s ?
b) Gia td’e cua nd bang -3 m/s ?

1.15. Vdn td’e ban ddu cua mdt vat chuyin ddng dge theo tr
toa dd. Bilt gia tdc ciia nd khdng ddi la 8 cm/s
nd dgd’c
a) Vi tri ciia nd sau 2 s.
b) Vdn tdc ciia nd sau 3 s.

11


1.16. Mdt electron ed vdn tdc3.10^
ban
m/s.
ddu Ndu
la nd chiu mdt gia
8.10^’^m/s2thi:

a) Sau bao ldu nd dat duge
5,4.10^
vdnm/s
tdc?
b) Quang dudng nd di dugc la bao nhidu trong khoang th

1.17. Mdt may bay phan luc khi ha canh cd vdn tdc tilp d
datmay
dugc
dl giam td’e dd, gia tde cue dai thi
cua
baybang
cd - 5 m
a) Tfnh thdi gian nhd nhdt cdn dl may bay diing han la
b) Hdi may bay nay
ed eanh an toan trdn mdt dudng ban
thiha
dugc khdng ?

1.18*. Mdt ban hge sinh tung mdt qua bdng eho mdt ban kha

4 m. Qua bdng di ldn theo phuang thang dung va ban na
qua bdng sau 1,5 s.
a) Hdi vdn td’e ban ddu cua qua bdng la bao nhidu ?
liic
ban
b) Hdi vdn tde eua qua
bdngnay bat duge la bao nhidu ?
1.19. Mdt ngudi nem mdt qua bdng tuf mat ddt ldn cao theo
van tdc 4 m/s.
a) Hdi khoang thdi
gian
giiJa
hai thdi dilm ma cua’qua
van tdc
bdngcdcung
dd ldn bang 2,5 m/s la ?bao nhidu
b) Dd cao
liic
dd bang bao nhidu ?

1.20*. Mdt vat rod tu do, trong giay cudi cung rod duge 3
liic
bat ddu
reddd’n luc cham ddt.

1.21. Ngudi ta tha mdt
hdncita
das6 d dd cao 8vdd
turmdt
m mat

so ddt (vdn
mdt hdn bi thep rod tuf trd
ban ddu bang khdng) vaoliic
dung
nhau
xud’ng di ngang qua vdd vdn tde 15 m/s. Hdieach
hai
vdt mdt
ch
khoang thdi gian bang bao nhidu
? Bdciia
qua khdng khf.
stie
can

1.22*. Dl bid’t dd sau ciia mdt cai hang, nhiing ngudi th
thadin
nghe thdy tilng vgng
midng hang va do thdi liic
gian
tur liic
da khi cham ddt.
sit
ngudi
Gia
ta do dugc thdi gian la 13,66
eua hang. Ld’y gia tdc trgng trudng
m/s^va g
van
= tde

10 am trong
khflavam= 340m/s.
1.23*. Mdt hdn bi dugc
redtutha
do, van tdc ban ddu bang
Sila 0.
dd Ggi
ddi
hdn bi sau giay ddu tien.

Sjtrong
nhiing khoang thdi gian
a) Hay tfnh dd ddi cua hdn
bi theo
lidn tilp va1bang
s.
12


b) Haytinh
hidu cua cae dd ddi thue hidn trong nhihig khoa
sd’khdng
ddiban
va
nhau lidn tilp, bang 1 s va nghidm lai rang
hidu dd
bdng 2si.

1.24. Luc trdi khdng cd gid, mdt may bay bay tii dia dilm
mdt dudng thing vdd vdn tde khdng hit

ddi2 100
h 20m/s
min. Khi b
ndngid
tii
B vl A may bay hit
bay
2 h 30 min. Xacvan
dinh
td’e
trd lai, gap
cua gid.

1.25. Trdn mdt con sdng chay vdd van tdc khdng ddi
m/s,
bod0,5
ngugc
tiic
quay trd lai vl vi trf ban ddu.
ddng 1 km rdi ngay
lapbed
bod eua ngudi dd la bao nhidu ? Bid’t ring, trong nudc
van tdc 1,2 m/s. Hay so sanh vdd thdi thi
gian
ed
bodngudi
dugc dd
trong
ddng sdng lang ydn (khdng chay).

1.26. Mdt phi edng mudn may bay cua minh bay vl hudng Tay
cua e
vl hudng Nam vdd van tde 50 km/h. Bilt rang khi khdng
may bay la 200 km/h.

a) Hdi phi edng dd phai lai may bay theo hudng nao ?
b) Khi dd vdn td’e eua may bay so vdd mat ddt la bao nhi
1.27. Mdt d td chay vdi vdn tde 50 km/h trong trdi mua.
kfnh bdn cua xe, cdc vdt mua roi lam vdi
thing diing. cita
Trdn
dung mdt gdc 60
a) Xac dinh van tdc ciia gigt mua ddi vdi xe d td.

b) Xac dinh
vantd’e cua gigt mua dd’i vdi mat ddt.
td Btdc
chay
1.28. 6 td A chay thing vl hudng Tdy vdi6 vdn
40 thing
km/h.
hudng Bdc vdd van tdc 60 km/h. Hay xae dinh van tdc ci
ngudi ngdi trdn d td A.

1.29. Mdt nhdm hgc sinh lam thf nghidm chuyin ddng
trdn
eua
mdt mdt
mang nghidng ddm khf. Mang nghidng mdt gdc so
ngang.

vdiVan
mattdc
nam
tlie thdi cua xe duge ghi nhd mdt cam biln quang didn n
thi.
Trong mdt ldn
nghidm,
thf nhdm hge sinh nay da kit
ghiqua
dugc
sau:
Toa dd (cm)

20

van tdc (m/s)
0,386

40

60

80

100

0,560

0,687

0,791

0,884

Hay tfnh gia tdc ciia xe vdd gia thilt xe chuyin
diu. ddng n

1.30. Ngudi ta lam thf nghidm do gia td’e rod thep.
tu do
Siicua
dung
mdt
mdt bd phdn do vdn tdc ndi 1.29
d bai
dl do
tdpvan tdcbirod
hdn d eudi
13


nhung quang dudng khac Cac
nhau.
kit
qua thf nghiem dugc. gh
bang sau :
Toa do
(em)

20

40

60

80

100

120

140

van td’e
(m/s)

1,980

2,803

3,433

3,964

4,432

4,848

5,238

Gia tri cua gia td’e rod tu do g do dugc trong thf nghi

Quy luat vl rod tu do cd duge nghidm diing khdng ?

1.31. Mdt chdt dilm chuyin ddng trdn true Ox. Phuang trin
ed dang sau :
X = - 1 + lOt+ 8,
t tfnh bang giay, x tfnh
Chgn eaudung trong eac cau sau :
Chat dilm chuyin ddng
diurdi cham ddn
diutheo ehilu duang cua true Ox.
A. nhanh ddn
B. nhanh ddn
diurdi cham dan
diutheo ehilu dm eua true Ox.
diurdi nhanh diu
ddntheo chilu duong cua true Ox.
C. cham ddn
D. chdm ddn
diurdi nhanh diu
ddntheo chieu
am eua true Ox.
E. cham dan
diutheo ehilu duang rdi nhanh
diutheo
ddnehilu
am eua
true Ox.
1.32. Hai xe A va B chuyin ddng trdn ciing
V (m/s)’
I

mdt dudng thing, xudt phat tii hai vi
tri each nhau mdt khoang bang /. Dd
thi van tdc theo thdi gian eua chiing
duge bilu diln trdn mdt he true toa
dd la hai dudng song song (Hinh 1.3).
cau nao sau day la diing ?
A. Trong khoang thdi gian
ti,tii 0 hai xe chuyin diu.
ddng
B. Trong khoang thdi gian
ti,
tuf 0 hai xe chuyin ddng cham
diu.ddn
C. Trong khoang thdi gian
t],tii 0 hai xe chuyin ddng nhanh
diu.ddn
14

Hinh 1.3


D. Hai xe cd cung mdt gia tdc.
E. Hai xe ludn ludn each nhau mdt khoang cd dinh, bang
turmat
xud’ng
1.33. Mdt thang may chuyin ddng khdng van
tdcddt
bandiddu
gilng sau 150 m. Trong 2/3 quang dudng dau tien, thang
chodin

khiddn
trong 1/3 quang dudng sau, thang chuyin diu
ddng
cham
dtmg hin d day gilng.

van tdc cue dai ma thang may dat dugc la gia tri nao sa
A. 5 m/s.
B. 10 m/s.
C. 30 m
D. 25 m/s.
E. 40 m/s.
1.34.Ciingbai tap trdn, hdi gia tri nao eua gia td’e trong
(Chgn chilu duong true Ox hudng xudng dudi).
A. 0,5
m/s^
D. -1m/s^

C. 1 m/s’

B. - 0,5m/s
E. - m/s^
2

1.35. Trong mdt thf nghidm xe lan tren mang nghieng, ngudi
cua xe tai cac thdi dilm khac nhau trong bang sau day :
Vitri

A

B

C

D

E

G

H

t(s)

0

0,4

0,8

1,2

1,6

2,0

2,4

1,5

12,0

21,0

28,5

34,5

39,0

42,0

x(cm)

a) Hay xac dinh gdnvan
diing
tdctiie
thdi eiia xe tai eac vi tr
E va G.
b) Tfnh gia td’e trung binh trong nhung khoang thdi gian
Em ed nhan xet gi vl chuyin ddng nay ?

1.36. Trong mdt thf nghidm trdn mang nghieng eua dem khf,
dan 20
ms (1 ms la 1 mil
dugc ghi lai sau cac khoangdiu
thdi
gian
bang 0,001
s) trong bang sau :

Vitri
x(mm)

A

B

C

D

E

0

20

35

45

50

Hay xac dinh gdn diingtiic
vdn
tdetai cacB,vi
thdi
C, D.
tri
15

1.37. Mdt chat dilm chuyin ddng trdn mdt dudng trdn ban k
eua nd khdng ddi, bang 4,7 rad/s.
a) Ve quy dao eua nd.
b) Tfnh tdn sd va chu ki quay cua nd.
e) Tfnh td’e dd dai va bilu diln vecta vdn tdc tai
each nhau 1/4 chu ki.

diutrdn
1.38. Mdt ehdt dilm chuyin
ddngmdt quy dao trdn, ban kfnh
rang nd di dugc 5 vdng trong mdt gidy. Hay xac dinh
hudng tdm eua nd.

1.39. Xac dinh gia tdc hudng tdm cua mdt ehdt dilm chuyin
trdn ban kfnh 3 m, tde dd dai khdng ddi bang 6 m/s.

1.40. Dl chudn bi bay trdn cac con tau vii tru, cac nha
trdn may quay li tam. ghi
Gia
sitd each tdm cua may qu
ngdi
khoang 5 m va nha du hanh chiu mdt gia tdc hudng tdc
tdm
trgng trudng
Hdi:
g.
a) Td’e dd dai cua nha du hanh bang bao nhidu ?
b) Td’e dd gdc bang bao nhidu (tfnh ra vdng/phut) ?

thibudc
1.41. Tii trudng
cd mdt hat mang didn chuyin ddng theo md
Gia sit
trong
turtrudng, mdt dlectron cd gia tdc hudng tdm la
td’e dd dai cua nd bang bao nhidu nlu ban 15
kfnh
em ?quy dao

1.42. Trong hd quy chid’u gin vdd tdm Trai Ddt, Trai Ddt
quanh true Bdc - Nam hd’t mdt ngay ddm. Coi Trai Ddt
kfnhRj)= 6400km.

a) Tfnh td’e dd dai dilm
euanam
mdt d xfeh dao, va cua mdt
vidd
di
45 Bdc.
b) Trung tam phdng
l&atdn
vu tru eua chau Au ddt d Ku-ru, G
Phap) nam gdn xfeh dao. If
Hdi
vdd
do vdt
Ifnao, ngudi ta lai ch
dd?

c) Phai phdnglita
tdn
vii tru theo hudng nao dl ed lgi nhdt

1.43. Khi lam thf nghidm vl ddng hgc, ban Vdn da ghi dugc
dudi ddy (Hinh 1.4). Hay trinh bay va giai thich hai
vdn td’e
tiic
thdi cua vdt chuyin ddng tai thdi dilm t = 0,
16


t(s) x(cm)

x(cm),
50

0

0

0,1
0,2

2,2

0,3

10,2

30

0,4

15,8

25

0,5

23,0

20

0,6

31,4

15

0,7

40,8

0,8

5,6

45
40

35

*

10

M

5

51,5
0,1

0,2

0,3

0,4

0,5

0,6

t(s)
0,7 0,8

Hinh 1.4

1.44. Mdt ban da lam thf
X (cm)

nghidm chuyin ddng cua
bgt khf trong d’ng thing va
ghi duge sd lidu rdi ve dd
thi nhu Hinh 1.5. Mdi
dudng thing trdn dd thi
ung vdd mdt gdc nghidng
ciia dng.
Hay phdn tfch va xdc dinh
tinhchdt cua chuyin ddng
cua bot khf.

Hinh 1.5

2-BTVL 10(NC)-A

17


DONG LUC HOC

CHAT D I M

I - BAI TAP VI DU
Bail
Mdt vdt cd khd’i lugng m = 2 kg,
chuyin ddng dudi tae dung cua mdt luc
keo F]jbiln ddi theo thdi gian, va mdt
Fj,ed dd ldn khdng ddi la 2 N.
lue can
Dd thi van td’e eua vat nhu trdn

Hinh 2.1.
"
Hay ve dd thi bilu didn su bid’n
thidn eua dd ldn luc keo theo thdi gian.

10 t(s

Bdi gidi
Niu-tan
Theo dinh luat
II :
F(N)|

F,,-ma
+ Fc

dodd

(1)

4

Trong 2 giay ddu, van
dd tde
thi
la mdt doan thing dd’c ldn, vat chuyin
ddng nhanh ddn
diuvdd gia tdc :
a =

Av
At

2
. .2
= = 1 m/s
2

:F^= 2.1+ 2 = 4 N
Thay vao (1)

8

10t(s)

Hinh 2.2

Trong 4 gidy tilp theo, dd thi van tdc la doan
true
thing
hoanh,s
diu,
gia tde a = 0. Theo cdng thiic (1), ta ed
vat chuyin ddng
Fk = Fc = 2N
Khi dd lue keo can bang vdi lue can.
18

2-BTVL 10(NC)-B

Trong 4 giay cudi, dd thi van tdc la doan thing ddc xud
chdm ddndiuvdi gia tde :
Av
a =
At

0
4

-= -0,5
m/s

Theo edng thiic ed:
(1), ta
Fk = 2.(-0,5)
+ 2 =
1N

F^keo
theo thdi gian dugc bilu didn nhu trdn H
Dd thi cua luc
Bai 2 (Bdi tap trdc nghidm)

m2
Vo

?X:

^7777

Trong Hinh 2.3,
mi = 0,5 kg ;
/
/
/
/
m2 = 0,8 kg ; hd sd’ ma sat nghi va hd sd
/
/
/
m2 vavdt
mat ban
diu
ma sdt trugt giiia
/
/
/
la |u= 0,2. Ngudi
giii
cho
ta hd ddng ydn,
/
/
mi
/
/
rdi truyin rh2
cho
mdt van tdc ban ddu
/

A
VQ cd hudng
nhuhinh
ve. Hay chgn cau
Hinh 2.3
md ta dung vl chuyin ddng
1 :eiia vat
diuldn
A. vat 1 chuyin ddng chdm
ddntrdn, dd’n mdt dd cao nhd
xud’ng dudd.
chuyin ddng nhanhdiu
ddn
B. Vdt1 chuyin ddng
diuldn phfa trdn.
C. Vdt 1 chuyin ddng cham
ddn trdn
diuldn
dinmdt dd cao nhdt din
dumg lai.

D. Cd thixay ra mdt trong 3 kha nang ndi trdn,ldn
tuy
cuaVg.
thudc v

Ggi y:
Khi lam loai bai trac nghidm, cdn vdn dung kiln thiic
loai trii nhiing phuang an tra ldi sai va lua chgn phuang

Sau khi vdt 2 duge truyin
VQ, vdn
trgng
tdcluc
Pj (hudng xud’ng dudi

Fms (hudng sang phai)
diucd tdc dung can trd chuyin ddng eua
diudugc. Ta loai ngay cdu B.
khdng thichuyin ddng

Cdu A va cdudiu
C cd y ddu diing (hd chuyin ddng
diu).
chdm
Sau ddn
khi
hd diing lai, trgng
Pi cd luc
xu hudng keo
1 di
vdtxud’ng va keo vat 2 di
19


phai. Lue ma sat lue nay se hudng sang trai dl can trd ch
vdd gia
tri cue
F^j^cua
dailUc

chgn giiia eac kha nang A va C taPiphai
so sdnh
ma sdtnghi:
Pl = mig = 0,5.9,8 = 4,9 N
F^, = nm2g = 0,2.0,8.9,8 = 1,57 N

Vdd sd lidu cua bai nay ta dd
thdy
Pi >dang
F^,^.
Vdy, sau giai doan
ddng cham ddn
diu,
hd khdng dumg lai ma se chuyin ddng
diu
nhanh
theo
ehilu ngugc lai, A dung.
(Ne’u sd lidu trong ddu bai
Pi< Fn,^
ddnthi
dd’n
C diing).
Trong cdc ldp ludn tren, ta thdy
VQ khdng
dd ldnanh
cuahudng ddn
hudng didn biln cua hidn tugng, vay ta loai D.
Bai 3
Mdt chid’c ban trdn ban kfnh

R = 35 cm, quay quanh true thing diing
= 3 rad/s.
vdi vdn tdc co
gdc
thidat mdt vat nhd trdn
Hdi ta cd
vung nao cua ban ma vat khdng bi vang
ra xa tam ban ? Hd sd ma sat nghi giiiaHinh 2.4
vdt va mat ban
|J.=la0,25.
Bdi gidi

Vdt se khdng bi vang di nd’u luc ma sat nghi cua mat ban
luc hudng tdm
:
F^^^= F^t
ma

F^sn^ ^^mg;F^t= m o ^

d ddy r la khoang each
dintii
tam vat
ban, Hinh 2.4.
Tuf dd :

m(o\< |a mg

^0^^ g _ 0,25.9,8
(o

3
vay, dl vat khdng bi vang, ta cdn dat nd trong phamvdd
vi
ban, bdn kfnh 27 em.
(Dap sd nay chdp nhdn dugc vi r < R).
20


II -Bi BAI
2.1 Hay xac dinh luc do vdt nang lam cang
cac ddy AC, AB. Cac sd lidu eho trdn
Hinh 2.5.
2.2 Chgn edu dung.
Khi dang di xe dap trdn dudng ndm
J ngang, nlungumg
ta dap, xe vdn di tilp
chiichuaditng
ngay. Dd la nhd
A. trgng lugng cua xe.
B. luc ma sat.
C. qudn tfnh eua xe.
D. phan luc cua mat dudng.
2.3. Giai thfch tac dung cua day an toan trdn xe d td.

2.4. Giai thfch tdc dung cua cae dudng bang trdn san bay
ha canh cua may bay.
2.5. Rdt khd ddng dinh vao mdt tdm van mdng va nhe. Nhun
dl thi
dang
ddng

vdt na,o dd vao phfa bdn kia tdm thi
van
lai
ed dugc
Vi sao ?

2.6. Chgn cdu phat bilu dung.
A. Nd’u khdng ed lue tde dung vao vdt thi vdt khdng ch
B. Nd’u thdi khdng
dimg
tdc
luc vao vat thi vat dang chuyin
dumg lai.
ddng
C. vat nhdt thid’t phai chuyin ddng thso hudng ciia l
D. Nd’u cd luc tde dung ldn vat thi van td’e cua vat bi
2.7. Mdt qua bdng cd khd’i lugng 0,2 kg bay vdi
dindap
van vudng
tdc 2
gdc vdi mdt
biic
tudng rdi bi bat trd lai theo phuang
15m/s.
cii
Khoang thdi gian va cham bang 0,05 s. Tfnh luc cua tu
bdng, coi lue nay la khdng ddi trong sud’t thdi gian t
2.8. Luc Fltac dung ldn mdt vat trong khoang thdi gian 0,8
thay ddi
tit

0,4 m/s
din0,8 m/s. Luc F2
khac
tde dung ldn nd trong

thdi gian 2 s lam vdn td’e cua nd thay
ddi
0,8
din1
m/stur
(Fiva
Fj m
ludn ciing phuang vdd chuyin ddng).
p
a) Tinh ti sd , bilt rang eae luc nay khdng ddi trong
F2
b) Nd’u luc
F2 tde dung ldn vdt trong khoang thdi gian 1,1
vdt thay thi
ddi nao
?
21


2.9. isidt luediing
tac
vao mdt vdt trong khoang thdi gian 0,6 s
5 cm/s (luc ciing phuong vdi chuye
Ti^
nd thay ddi tur din

8 cm/s
dd, tang dd cua
ldn
lue ldn gdp ddi trong khoang thdi gian
giii nguydn hudng
eua
lue.
Hay xae dinh vdn tde cua vdt cudi.
tai th

2.10. Mdt lue F truyin eho vdt mi
ed mdt
khdigia
lugng
tdc bang 8 m/s
cho mdt vdt khac ed khdi
m2 mdt
lugng
gia tde bang .Nlu
4 m/s
dem ghep
hai vdt dd lai thanh mdt vdt thi lue dd truyin cho v
bao nhidu ?

2.11.Mdt vdt cd khdi lugng 3 kg dang chuyin
diuvdi
ddng
vdnthing
VQ
tdc

= 2 m/
thi chiu tde dung eua mdt luc 9 N VQ.
ciing
Hdi chilu
vdt se vdi
chuyin
10 m tilp theo trong thdi gian la bao nhidu ?

2.12. Mdt vdt khdi lugng mchuyin
= 0,5
ddng
kg nhanh ddn
diuvddvdntde ba

ddu VQ = 2 m/s. Sau thdi gian t = 4 s, nd di duge quan
rang vdt ludn chiu tac dung Fk
cua
va lue
luc keo
can
FJ.= 0,5 N.

a) Tfnh dd ldn cua luc keo.
b) Nd’u sau thdi gian 4 s dd, luc keo ngiing tac dun
dumg lai
?
2.13.Mdt vdt nhd khdi lugng 2 kg, luc ddu dting ydn. Nd
Fi= luc
4 N va
F2 = 3 N. Gdc giiia

Fi va F2 la30 .
ddng thdi eua hai
Tfnh quang dudng vat di dugc sau 1,2 s.
2.14. Hgp lue tae dung ldn mdt
xe d td bid’n thidn theo dd
thi d Hinh 2.6. Bilt xe cd
khdi lugng 2 tdn, van td’e
ban ddu bang 0. Ve dd thi
vdn tdc cua xe.

-200
2.15.Hai ngudi keo mdt sgi
ddyf
Hinh 2.6
theo hai hudng ngugc
nhau, mdi ngudi keo mdt
lue 50 N. Hdi sgi diit
ddy
cdkhdng nlu nd chi chiu duge lu
hay
la80N?
22


2.16. Tfnh gia tde rod tu do d dd cao 5 km
nita
va
band kfnh
dd cao
Trai

bang
D
Cho gia tdc rod tu do d mat ddtm/s^,
la ban
g = kfnh
9,80 Trdi Ddt
R = 6400km.

2.17. Hay tra cliu cdc bang dii lidu d phu luc 2 cua SGK d
ddn giiia Mat Trdi va Trdi Ddt.
2.18. Nlu bdn kfnh cua hai qua cdu ddng chdt va khoang
ehung cung giam di 2 ldn, thi lue hdp ddn giiia
chung
thd’
nao
? t

4 ^
(Qua cdu ban kfnhthi
rtfch
cd la V = - nr).
3
A. Giam 8 ldn.
B. Giam 16 ldn.
C. Tang 2 ldn.
D. Khdng thay ddi.
2.19*. Lue hut cua Trai
da^vao
Ddt
mdt vat khi vat d mat ddt la 45 N,

cao h la 5Chgn
N. gia tri diing
cuah :
A. 3R.

B. 2R.

C. 9R.

^R. D.

(R la ban kfnh Trdi Ddt).
2.20. Cdc gigt mua rod dugc xud’ng ddt la do nguydn nhan na
A. Qudntfnh.
B. Luc hdp ddn ciia Trai Ddt
D. Luc ddy Ae-si-met eiia
’ C.Gid:
2.21.Khoang each trung binh giiia tam Trdi Ddt va tdmIdh
Mat
ban kfnh Trai Ddt. Khdi lugng Mat Trang nhd hon khdi
81 ldn. Tai dilm nao trdn dudng thing ndi tam eua chi
Ddt va eua Mat Trang tac dung vao mdt vat can bang nhau

2.22. Mdt tdn
lura
vu tru dang d each tam 1,5.10^
Trai km.
Ddt Luc hdp ddn c
tdcdung ldn nd d vi tri dd nhd hon so vdd d mat
Trdi Ddt

Cho ban kfnh Trai Ddt
R km.
=
6 400

2.23.Mdt qua bdng nem theo phuang ngang vddvgvdn
= 25td’e
m/s ddu
va r
xudng ddt sau t = 3 s. Hdi qua bdng da dugc nem tur dd
xa eua qua bdng la bao nhidu ? Bd qua luc can eua khdng

2.24. Mdt may bay bay vdd vdn tdc
VQ theo
khdngphuang
ddi
ndm ngang d d
h so vdd mdt ddt va tha mdt vdt.
a) Nlu h = 2,5VQ km
= 120
;
m/s ; hay :
+ Ldp phuong trinh quy dao cua vat.
23