“Date: Qa) 1alaoae
Cuaprer
System of Particles AND ROTATORY MOTION
fs arigid body?
What
 
I+ Vs the body whose Shape and sfz2e@ does no
change ondey the actfon of force 1
TYPES OF MOTION OF RIGID BODY
WN EO
=7 Transtatoxy motion
=P Ratatfonal motton
wIRANSLATOTY Motion
ee
T+ Ps the medfon PA conch all the parifcles
of a ytd body moves wiht @ same velocthy
at any Fat Instant of tme-
Ex i Motfon of a stone dvopped from a
paxtPeular hetght>
@ ROTATIONAL MOTION
Re
I+ ?s the motfon Fn which ail the porifetes
of a v¥gtd body moves fn a cPycle about a
fPxed axfs.
Exi Rototfon of Earthy about Pts ousn axts
Rotatfon of a wheel
 
@ DieFeRENCES BETWEEN CENTRE OF MASS AND
—eo€_—errr
CENTRE oF GRAVITY ~~—~~~
~~ Lt
Centre of MASS
 
   
   
ee ee eee CentRE OF GeauitY
T+ Ps the point at cht
fhe whole mass of He
body %s Supposed to be
Conten tratea:
Tt Ps the pont at
tohfch the ushole wefght
of the b i
eee ody fs soppy.t+ depends onty on ° T+ depends on .
" gett buon of mass ALskP LAN OF Mass
\ OANA gravPtatPonal Freid.
 
s PostTiON OF CENTRE OF MASS OF SUSTEM OF
TWO PARTICLES, OP TWA DIMENSIONAL
An ~~
>
 
—
 
me
0
7 re =
een Cc
OG
< Ky
INTRODUCTION 2 Inthe above dlagram m, and mM)
ave the masses Of hoo particles
K,and x, ave the posfifon of hoo parifcles
from the Ovfgtn-
“is the. postiPon of centye of mass of System
of pawtfeles -
Along ~« axfs the postion of 1% of centre of
mass Ts given by
Pg te Mm, wH, tomy, wx,
ey
mt
MENTION AN EXPRESSION For POSITION COORDINATE
PARTICLE SYSTEM IN SPACE OR SO
Ree Pe Ee,
Along %-axPs tne postiPon 1% of centre of
Mass Ps gtven by
we Uw EK
Oy tas
Distance Pron ortg in. Along y-ads postifon y of centre of mass fy
gtven by
Myre yy
mtn,
f mass 7.
* Along 2 axfs postifon 2 of centre © Fs
given by
MrZy,t ON Zr
mMmtmMs
Alo enevral CR? posttfPon R of centre of mass
oo Fr
vs given by
Mee Myre
mam,
@ Position Coorninates oF Ns PARTICLES SYSTEM
IN| Fedo SPACE.
ee ee ee ee
‘ Along mu ax?s
WF CW Mp TOD Wat MV AMY + PHS. TMM
ner
Mita tema t eee M9
Along neers
gem + eye t ria yy be... tmagn
. ‘Along Zaxtfs .- :
A= Bh Za Ma Zag $M 3 Doe weet penn
PU ta eee lion,. in General A
R= my) t+ Marit M37v, bmn
 
CATT AM aA eee OD
Re eme wp
M
 
Me Mtr tater! MA
wp TERMS IN RELATION WITH ROTATIONAL NOTIons
en
Angp lax alsplacement Ce)
Angolar VelocPhy Cus)
Angvlar accelex~atfon Cx)
Tow qrpe Cw
Angvlay momento GL).
Kfneh?c energy
Moment of Tnevtfa Cr)
=7 Radfos of gyratfPon Cred
 
m Angucar Dispracenentr Ce)
ee ee
T+ %s the ORALe descw? bed by a vodfus vector
In a gtven +me-
O= Ave Length = 40
vadfus +
 
  
  
    
 
S-T unt+ of angular d&splacement Ps Radfan
Radfan CRad) Cradd
w
Amqueae Vevoeity Cus) omega
Rate of change of angvlay alsplacement per
ont time Fs caued angolay vetocthy-
w= Ao 3 S-D unt 2 sad =2 vad [se es
at sec vad sec!° Angular velocthy fs a Vector quan tty -
 
" Anqucar Acceleration
Ons
‘i |
T+ ts deffred as thevatfo of the change fn |
angular velockty of the body and the +fme
taken
Angular accelevadeon = change Pr angvtar veloc
See ee
Time taken
= FPnal Av- IntHal Av
+
cL = ud. - “Oe
 
 
 
+t
* ST ontk = vada /sec®
Retaktfon betwoeen Ifneax and Angular ace elevate
 
 
LB marks
=? Ve=~us ie ies nacail '
DiFfeventPating™ both sPaes US¥ +o 4+re.
dv 2 ASCrus) |
at at 7
aA = YAW |
AL |
A=yu
 
 
 
gm Moment of Tnertia
_—eS
 
Moment of Inewt?a of & bedy aboot a giver
©;
axis %s deffned as Sum of product of moss |
of each part¥cle and squave of MHS pe |
_ulay dfstance from Me axts oF xStatfen
"|
: a_— ~~ 2 ~—
w Expresston fox moment of Inby+fa of the
eee
ae a
body
TH Su, Mz -Ts Sts ome Me
masses of part&les of O
Pg id body strated at a
alstance of Y1,¥%2,43 From
whe axts vespectPvely ,thren
moment of PnertPat
 
2 2 2
TamMM TAM vo t+ O73 Va eee my,y¥,t
T= Emv?® Kg om?
 
w Factoxs on eah?ch moment of a evtfo, depends
eg ee
 
e Mass of the body
+ BYstance Prom axfs of xo tat Pon
+ Sfze and shape of the body
©¢ S-I untt+ 2
 
Kg ro
@ Toraue
AARRE B_LMOMENT oF Fonce:
Terqgve acta
ON A body about anaxfs of
YototPon %s Gefed as the
vS Product of
moagothde of Rxce actif
ON A part¥ele and
Pevpend2culax a&stance behoseen ‘tae Pre of
ACHPeN of force and axfs of yotatfon
BExpression For TORQUE
SSGGERSIEN,
‘ Tel ET yay
wheve F Ps force acl¥rg on the partfele
anda ~ Fs 4he radfus vector or pev pen d&eulay
stance behoeen
IWNe of actPon OF hoo
forces.
Eeeee
e Torque Ps a vector quanti hy
* SeL untt of Torque Ps Newton Metre Nn
+ Torque fs the vector product of hoo vectors
—
ae = ET oye
= FY Sind
“T8s max = 8 =9Q0°
TT Fs mPas @ = 0°
w Relat
elation behoeen Torque and OLPh a oc
 
—T =e. _
Pe est
= fey
= Maer (f&=may
= wer
ane Gino ees
Total torque = & mun Crav2=2)
Vs De
"Easterns on conten tore ‘depend s
so as
“Magnitude of force
* Perpendfevtay afstance behoscen ne of
Act¥ON of hoo forces?
= Awnqucar Momentun
AAS PME TOM
Angrlox Momentum of a pavifcie '%s dened
as the product of tPrneax Omen tom and
per pendtevlar d&stance of the Parteele from
the axis of votatPon «
oR
The moment Of near Mementom eof a
xAecle aboot AN axls of votaton.
PaLt - =
ir Ps senesced by the letter L
L= Pix ¥7 ,
|
= py sine
TE =O 3 angelay Mementem Fs maAfmom
= L=OoO
 
Te @=90°5 angvlay momento Ts max
= = Eaw ©
.$L untt of angolay momentum 7s Kg m/sec
L=~*P
= GO ™ (vere)
= ym
= maw?
L.
L = €& my?49
ae a)
AR MOMENTUM AND TORE
Tox gee
 
 
Retatrion BETWEEN AN GLU
aA SA
EOI Cs oe
Differe nifoting both sides wth yespect to +#me
ustng a
aU! _ a. CPR)
Ke
 
Tak
= (Fe BE) A 87, )
=(pt 1s ACHR ET) fi
= (eS TS CED
Soot CURED) CTS Zl=0)
A*/ go4y Fo OT :
Teraqye = rate of change oF
angula® raoment™BW Comstavation oF ANGULAR MOMENTUM
OER
TF the total externat torque actPag on the
SyStern of paxitcles ox +Pgtd body “fs ze ¥o 5 then
the 4otal angulay momentum of the system fs
Conserved o¥ constant
We hove Angutaw momentum L = Tvs 5 where
T= moment of PntextPa and 6d = ANngvler velockh,
According te. Laus of consevuatfon of angular
Momentr Es of
Tus =constant
Therefore PF TL decreases
the 09) wit Pacrease
and vice versa.
mw Examples
Nae
ZA dlver Tempting from ao Spying board folds
hes oxms and legs fn wards As ayesutt of |
MTS Moment oF 4 Previta Aeleveases 45 conserve
angulay mementum h?s angular velocthy Treveases
Therefore, duxtng Jumptng hee can votate Pa
8s sth imaxtmom ang uta Neloctty
; = ;
7 A Bote+ dancey uses the prfnc&ple.o f
conservation of angular! moment tp Tacvease.
thet speed- They Staxt sptaning estik wet
axms Stretched Hen forv toe Wey Orms closer
as a yvesgolt moment of sero decreaces
and hence angular velocity yieas\s
m Cov PLE ‘ ‘
ee
2: ©.
° £ equal and opposite forces wfth
. ceed ae of action act€rg on an onfect
: E ° 2
eee eord body conshhte o coupte }
°gt untt of Couple NaC Newton Meter) |
     
~~ —_—_— 8
perpendiev lan
fc ligt auce
A Couple prodvces onty yotadfonal motton -
we Momen* of a Couple s- Ps defPned as the
i product of eosattee of any of the forces
and perpendtcolar dfstance between them,
(. re fs the votating abrity of a Couple:
 
Example ~
=7 A Couple fs applfed vsing ovr feagers +o
~votate Ifd of a bottle
(=T A Covuete Ps applfed usfrg ovx legs to peddte
a bfcycle*
Roows of Gussrion toe fate Shore
Radtee ihre"
Radius of Gyratfon af a body need mn axts
Ss the perpen d&evlay Afstance from the ax’s
to Re potnt at vohich entre mass of the
body Ts assumed fo be concentrated
Tr m 2s the naass of the body and k 7s
“the d&stance of the polat From the axts of
yotodfon at udh?Pch entYre mass of the body
Fs co acentrated then?
Tamir : 2
Wheve kK os catted vyadlus of gyrvatfon about &
Brven ax?s of votatron.Ke a
actors on wohfch yadfus of Gyratfon of body
depends fe NE et ae |
Coo een Mic eedaa
% SfTze and shape of the body
=T Axis of votatfon.
 
ROTATIONAL KINETIC Creer Oy
a=
 
Rotatfon Kinetfe energy Ps the energy
possessed by a System of parifcles shea
{4+ executes votatfonat motton .
 
 
Rototfon al KE = 17, 2+ Yen gua? 28 &
rete t Yam ny, 2 t=2\
WRT =? v=, U9 at 4
Nav, U9 Ve
2 ae
Rot Kee = ve Cea yy,tu9 Se
= Mauer Cmte my eyten maAvn2)
= VW2awr> Err>
es Rotoatfon al KeE = ']2 Tus ®
 
 
 
=7 K-E= Nop MV® =—G rans latory mot fon
— ° = 2 : :
=7 KeE= "/y Tus? 7 Rotatfonal mortfon
- {= } DAA 13
MomeAt Of Inevifa plays the Same vole
Pr retarPon al mot eon as omass Plays. Pal’
trans latory motPon-
Moment of Tnev Pa Pe. the votatfona}
analog fox mass PA! Hr Gn Sla tery mMmothton:
- ' 9
irLinear Motion RoTATLONAL Motion
mz neay as placement | © = Angulay ALSPlacement |
ve Final Vanear velocPhy Wes Fenal angular Velo ly
ve TaPtfat \Pnear Veloct hy wIF= Tnhthal ange lar velocthy
as accelevatton <= Angolay aceelerat Pon, |
 
a 7 EQUATION S — ke
Veutat Wer = bogeet
ae
Ns urt Zar Wpr=09;24 AKO
Hever | 2
° = © = wWrtt Yyne®
 
 
 
 
Prusical Qty Linear ROTATIONAL
| Ve loctty Vale w= Olt
| ©,
| AccetevarPon |. as veru mK = We- De)
} | aS a
| | =}
| : | |
| Force (Torqve Fema verte |
| |
— | ‘foam e Vo rus2 |
Work | é
| 02> Fac w=Te |
Power P= FV p= us |
|
| Mome ntu = ’ =
| ™ P=’ seAnGLLaAR
Terns
        
   
 
RELATION
VRE G8 SumBoc
TERMS
 
UmBoL |
     
  
|
Displacement * Angular | ©
| A&splacement
 
   
   
 
 
     
Vetocthy Vo) Angelar ot
| Veto ty J |
Accertevatton a Angvlar I ,
Pars
| accetevatfon | (eae
| !
Mass eal | moments TL laem
   
[of TnevtPa}
  
r
rc
"
>
<
Momen torn P Angela |
| Momentom
Fovee Fe Torqgve | Vsry
 
BW DERIVE AN EXPRESSION FOR VELOCITY OF CENTRE
EES oor MAS SOOO
ao oe eee
cm SF ONT, IN {we ee eee
M
 
Eocpressfon For velocthy of cmEe AN EXPRESSION FOR ACCELERATION OF
 
 
 
wo Der
Centre oF MASS
—7 a a C vem)
mom —_
at
-— & oh Seeieeee eS
at Mm
[A C “Tat Crow + Bat Crna Te )4--)
aot = = —e
BE Yy Coma Ra WD
where dvi Ss the acceleratten of fie st
at
powssPcle and
of the second paxt®cte-
Av2zlat TS the acceleratfon
 
 
 
—_+ = —— a,
MO ce = ONE Ha Aa torres Cevoss moltipl)
Net, Exteanac Force. +
—= es
=r — —~
Come Mm Cra, engage wemy
=r = =
Moem = Cmial + ma UL t--- D>
Mealem Ys the net external force acting on
a xigid bedy = Feu
=T 7 oP
Fes. = fF, +f. 4-3
where mar 9s the force acting on Fevst
partfele and mas Fs the force acting on
Second part cle -»
Shous that IPreax momentom remains constan
when the net external force acting on &
partfcte Ts zero
 
MVon Pmt myo 4 lll.
—v pager
Poem = PTH PL, Po
—S
If Fexs =O .
According +o Neuston 's ad law!
—c
ap = fae
At *
fp +
ae), =0 C derPuatue of a constan
lak = 2
Fs o>
ato nalp >
e + P Ts a constant =F
w Niecoamical Equiugrrin
ee eee
A AAgrd boay) fs SoPd 46 ' be In mMechantcal
eqklPbstum PF both IPneay momentyem and
ang vlax (mamentom ave, Kept) constant es?th
vespect to42me , = —s * '
 
@ TRANSLATIONAL EQutuBgRions +) r oso
A ~ighd body % sa2d to be Ta Hranstdldoney
CqullPer¥um PF PE ~wemnatn s
 2
 
*
—It§ —TtR ontts- t