Undergraduate
自然科學

普通物理(上)7

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Emily

Emily

Rolling, Torque&Angular Momentum、Equlibrium

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ページ1:

Chill Rolling, Torque, & Angular Momentum
S
S = RO
> Vem
ds
S-RO
有一點泥巴P的軌跡
-Vem
轉動
P
P
U=Vcm
M
o fom
Icm
=
No.
Date
dt
-
R
do
dt
hem = Rw 滾動
不考慮滑動
0
Ucm
U1=20cm
Uam
Vere
.移動
Ktotal = 1/2 Ip w²
71=0
• 擋泥板
• 泥巴賣$
=1/2(Ian + MR²) W²
Ian W²+IM(RW)
New P點,無移動動能
轉動動能
===
轉動
移動
Chry culture

ページ2:

No.
Date
P
Mg
6 有f造成純滾動(在點看時!)
ex:
0
N
My sing
Mguso Mg
[法]→0點有速度,有移動
10 16: 5 - Mgsino + fs = Ma² *
T = - f₂R = ICMα = Iam &
[快速法]
a-
My sing
M+Iam/k²
移動轉動
的
a=
Isino
=
-M95ino
①
[法]
若以點來看,P點沒有移動動能(看圖上的藍色)
=
-II - - (Mgamo) R - Ip (24)
+
a
R
-Mg sino R =
ICM + MR²)
R
a
Mg pino
a
M+ ICH/R²
FOX (D eq. we get fs = Mg_cine,
(+HR²
"/IC.M
Cheyrculture

ページ3:

If it is a
a=
-My sino
Mi
R2
fs
exp
M
Lsing
h
*輪胎要做可disk,不是ball
disk才能控制方向
disk, ICH ==MRZ
Masino
+ MRT/MR2
MR².
MgLpino
=
-
hoop ICM-MR²
y
M
2
Jsino
My pino
disk IOH=/MR²
M
。
R
No.
Date:
* 庸民的腳踏車胎
-M
質量分佈在外圍→工大
08
單車選手的輪胎是一整片
質量平均分佈 小
Sphere ICM = MR
I= BMR”,B=1号(趙治字嫌麻煩)
T
2
+ I CHW² + + MUM²
Mg Lsino - 1 BMR² (1 km
2
5
2
2
MUCH
TrH nghe ino
Ite
移動動能:IMILY = MgLomo
-(146) MyLoino
translation kinetic energy
Rotational kinetic
1+6%
B
energy
Hoop MR²
50%
50%
Disk IMR-
67%
33%
Sphere MR²
71% Sphere 移動最快
29%
WAH = FOR

ページ4:

No.
Date
Yo-Yo (溜溜球)
FR
AT
{ - Mg + T = Mark
+] =
§-Mq
=
0=-TRO IN = IR₂
q
Angular Momentum
=m(Fxu)
=Ymusine
=
=
Ypsina
p
=
=
=
a=
和只無關!!
z
Ysino P
hip
proof: l= m (rxz)
at
=
=
m (rxa + Uxu)
xma
=
Yx (2)
=
NO(自己和自己外積)
=
47-(FxP)
m
Pr

ページ5:

20
==
INEW = IUM + dMX"
No.
Date
¢ AMR² + dmx²²
F
NEW =
L
dM-pd
R
1+42
=
NEW
1-42
+
3
1-42
RM
3
M
*+ X
4 L
L
12
-42
P-
X
Torque RET
+42
| 4MR² + 1/2 ML-
RO
+
I-ML
LO
✓ I = 4MR²
C
Pivot
8
T=
=
=Ysino Fi
0
T
"
T=F
- Fx1
=
sinor
mament arm

ページ6:

No.
Date
。
I
at
ap
期
F = mat
T = r = matt
=
manr
= (mr³α
[Σt - 104
=ma
Netwon's 2nd low
In lotation dynamic
disc
+
=
√ T
AT
TTR Id
-TR
=
a=-9-m
J M+M
y
19
T =
ming
M+zm
*u£tb= (ho why ??)
a=
mg
M + 1 MR²
2
2m
M+M
**E's henton's las
MRR

ページ7:

* ≤K = kf-ki = w
=
三
= I met / mui = w (有移動)
INP²- Twi² = w (只有轉動)
*dw=ds
=
Feds
W=
Fids
=
(Fr)do
W= Tdo
=
Ferdo
= Ido
*Power
p = di
Ido
I do
dt
m
☑
U
a
F=ma
w-SFdx
k=mu
P = Fu-
W= ok
移動
工喂
Tw
p = 4.0
I
→ Q
→ W
→ α
→ T=Iα
→w= Sido
→ K=/2±w²
→ P=Iw
→ W=Ak
轉動
No.
Date

ページ8:

No.
Dale
A
ex
L=22
m
m
m
R
B
ring.
10=2
axis!
IA = Icm + m² (R+ 2)²
= 1/2 m²² + m/R+ 1/2 2 ²
=
=
2m² (R) +m (R+R)
433 MR2
IB = Icm + m²
>
Yum =
m/o) +MR+ m² [R + =\/>"
3m
=R
041 = 3mg sym
1
=
=
3mg x (DR) - 6mgR
ㄓ
6mg R = 1/2 Itatal w²
= 15.8mR²) w
細棒的Ium=0.
I =
2 mR²
立起来
·ring
再去
W=
g
I=MR
518R
#
Itotal
= IA + IB + Iv
=
5.8mR2

ページ9:

Ls = le + lz + lz + ... + lx = E li
# = * + * + + * x = 1 + 2 +
dt
No.
Date
:
T+z++ Tn = IText
IText
=
U=0
P
=Ypsino
= Ymusing
=
=
• Ysino mat
mgtd
ΣText
dt
If
ΣText = 0
Lī
=
:
my
1 =
Const
Tili
=
Ipwe
We
Th
Fx 7 1 0 Mow 3
We wi
Li
Chry culture

ページ10:

No
Date
借一個放在艙內質量小5倍的
齒輪應用角動量守恆
幫助火箭轉向(用內力,對外噴 fuel too waste!)
Q有一個
超大單擺
抵抗颱風
toT
星蜜化的時候
Li=Lf.
Iiwi = If we
就象漏洗澡水,放完那瞬間
最快
Izla
IIWI

ページ11:

Date
+ 300
Chiz Egulibrium
=0D constant
=
ET=0 & constant
Static Equilibrium
Stable Equlibrium
P=o, l=0
Unstable Equilibrium
The Requirements of Equilibrium
1017
=0 The vector sum
of all the external forces that
act on the body must be
Zero
=0 The vector sum of all external torques that act
on the body, measured about any possible point
must be foro.
Balance of Fore
[Fix = 0
Σy=0
Σk z =
= 0
Balance of Torque
= 0
ΣTy=0
Σt₁₂ = 0

ページ12:

No.
Dale
:
For simplification
we consider the case that all forces
lieīn x-y plane →子方向為轉軸
質
0
120
| Σty = 0
ny
I ky
=0
重心
The grantational force Fig on a body effectively acts at a
single point, called the center of gravity (cog) of the body.
if à is the same for all elements of a body, then the
body's center of gravity is coincident with the center of mas
009
*
mi, megv
=
==
⑦Thet = Xeg Fig = Xeg. Zi
0-0
Σkimigi = Neg Σmigi
Xicg
=
Zom 若均匀動場
1g可提,消!
Chry culture
Xum = Xuma
ㄚ mù
• →
g is uniform Xrg - Xxcm

ページ13:

No.
Date
ex
Fie
M
ex
A
肌肉施力
m
^
x=0
Σy=0
→ { Σty = Fe + Fir - Mg - mg = 0
=
g
2
=
| Σ Tz - Mg + mg. — - FrL
Try { \>m+M] Fox - (M+ing) Fr
T
in
Ball
M
i Σ Ty - T T mg Mg
Σ Ty = - Fx0 + Txd - MgD - mgL
TT - y mDt mL
F₁ = 7- (Mato) g
个
chry culture

ページ14:

No.
Date
ex
ex:
M
a
a
al
Fgx
M500153
是一個分數
{ΣFix = Fw - Figx = 0
| Σ Fy = Figy - Mq
=
= 0
→ Trgy - (Mem) g - (Tokg + 4.5 kg) x 4.8 m
=
1146.7 [N]
a
Σ Tz = = Fuw h + Mg — + mg &
Trw= Jax (4 + 1) = 98 × 7538 1 1 + V
=
2
tv
- 407 ENJ
m
Figx = Few = 407 [N]
Figx = Ms Figy
Σiz = -Fiwb + Mg (q
F
ga
93
a
b₁ + Mg (qa) + mg = = =
h (1/3 + Mq)
=
・Fiw - Figx
0
=0
• Few = Tigo = μstigy = μs (M+m) g
from 0, 0, we get:
②
Chrys culture
f = Hsh (M+m)
m
Ma
01538913172745)
712×76
3.72
3M
45
=
-0.85

ページ15:

ex:
Date
Fi
Fh
Can f = Can 15
Fir
=
A Mg
17μM
Σ Tz = T.a. - Mg·b - mg -— = 0
T = 26 (M+%)
a
2
918×215 (430 +855)
19
-
609 [N]
Tip-Th To Th=7 - 609 [N]
Z Fy = Fro-Mg - my → Fc = (m+M)q = (85+450) × 9,8
Q=372°
tan 5047
16090
Q=3.60K並不重合!
2
=
5047 IN]
=
7900 [N](牆給棒的總)
Can
Fall F
Elasticity 彈性
Stress
F
metal
A
(面積)
0
Yield strength
Stress = modulus
=
→
Strain L
.
strain
應力彈性係數應變
modulus of elastic

ページ16:

No.
Date
②往兩方扯
AX
③ 四面八方的力
✓
L+AL
44
==
E
Young's Modulus
+
Shear force
=
GXAL
个
Sheat modulus
AV
P = B. ^V
pressure
↑
Bulk modulus

ページ17:

趙治宇回來了接Chw.
17/2
F
Ali
AM
Picomivi
€16
年
y
X
Iz = z biz
F
Ameeri
- ZAME (WHI) MI
ET
W
WI
P
P=ZPi
P=MUCH
Fest=#
p-con
- const
->
T = 1×
l=rxp
L-Eli
L-Iw
Σ Text
=
X
li = rilisingo°
=
liz = lisino
|-
=
rismi visino
(rusino) Mili
=
VAME Vi
[Lz = I w
if Σ Text-o
const
D = mu
P
No.
Date

ページ18:

No.
Date
:
*
before
Iz
W=0
after
W
ex
W=0
Wi
Wo
Iz
Eventually, p
U-W₂R₂-WRT
(角速度不見得相等)
* Sidt = Firbt = Ilwf-wr)
P 7³L
Sfdt = sp = J
I
Iz
Li₁ = Lf
IW₁ = (11112) W
W =
I Wo
I+Iz
小 *
AL-FRATIIW₁-W.)
AL= Rst=I2 (W₂-0)
- =
I w₁-Wo
12W2
W2Iz
=
W₁I
W2=2

ページ19:

這題趙治宇以前考過
ex
%
H
++
Y
Pivat
W = ?
0=2
li
=
h
T
-4b4 = 11
1-vpsingo
= lmy
= Im Fige
2
2
If
No.
Date
AmJyn - ( } Me² + me²) w
W₁ = lm Jagh
Me+ml
; I total w² = olg
+ 15 m² + m² ) x l'ogh V
(√ Me²+ m² 1²)²
[ Mg { \\ copo] + mg 1 (1 copo) ] = U
6mth
0=0p+ ||
(m+M) (3m+M)
+

ページ20:

No.
Date
*任意門不可能存在,經過黑洞還經過什麼黑洞的肉會被撕裂。
*用鈾的碎片(指甲大)揾動火箭:核變,可用光速航行100年

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