Elasticity
Rigid Body- AA boduly s said to be rigid i. the relative
position o t s Constituent Particles remains unchanaed
when externad dejorming forces au applied to it.
The neasst approach o a rigid body is diamond or
Canborundum.
Actually no bedy is igid an eveH bocy Com
Com
be defovmed more or lis by he applicathon of suitable
force».
Irter adomic Forces
Tis the forcs between the atoms elue to elechostedic
interaction betwean he changes ob *he atoms.
Thesejorus ane eletrica in nawL and.ane actie
h the distance between the two ahms is o the order o
whun the two atoms ame
F
brought close to each othe
the distancea betwun thair
pobitivt nuclei anol electonn
louds et distubed and ro>
duu to his athrachve inter Attractio
aomic fov is poducud.
This authractive foru imcreases
U
with ducrease inr and beome
maximum at a Critical oistane
.8uond h i th athracive ro
tovce Stads dacreabin wi th
wther ducrease IMY.
, At a dtane . the irteratomic forca uill be zero anod
this distonu is Ccallud equlibium distanta.
hen the oitanu betweun two atoms fwther decreased
the indexatomic sforce. become repulsive and imcreases ith
decrease in Y.
TL
Th e Poten onesgs related with the interedomic force is
iven as
F:.
whn t h dis tncL betueun the two ato ms becomes Yo
becomes
the petential enugy t e Systm o t o aoms
enns
minimum and hunce he tuo atoms at sepahation To
ro
wil1 be in a state equiibnum,
i t h f u t h r decrese im r the ngahve valu ot hu
Potenial onunay decrea amd becomes zero ano than
atans postive valu with fuher eleerease in .
Intermolecudar Forces
It i the forcas bahwen the molecules due to ehcho
static interachion between he changes o t h e molecules.
Th fras ae also callud Vander waal fores
conel aA quite weak as Compasrd to inder-adomic jorcas
Fbrc betwtan two molecudes is gvun by
F Fat. + Frp
The valu ot Cmstants a anol b dupends upon thi Structure
Ond nahu o malecwes.
, Petential Enery Can be expressee a
U A
whna Yeprerts repulsive Conhibution and B
represends the athachve tonhibuion.
aEInteratomic forcas ahe So do loo times stronaer
than intermolecudan forcas
Elasticity
The propety o matter by virtue ob ohich a
bocdy tends to regain its orginal shabe and size a t e
the removal of dleforming forces s callud elasticity
Reason o Elasticity
A soid booy is Composed of atoms Or mole-
Cules. These atonms or mølecules a boumded tpaethe
by
by interatomie or intemolecuan forces and stay in stable.
euilibsam position.
when m exteanal force i applied to the body
hen rebtoring forces Come imto play olue to interatomic and
intesmoleculan fovces and bing he atoms to its
origma
position.
PentectyElasHe Body
The boy which pengectly regains its odignad
foTm om removimg he exteanal defor ming force, is
defined
as a perhectly elastic body.
EQuaste , Phobpher bronze etc
, Ptecty Plastte bocy
he, boey oloes mot have
any tendency to
recove its oiginal Com figwraton, on the removal ot
deforming force , then it is baid to be perhectly ebtie.
E. Putty, mud Paraffin wax etc.
Stress-
The inteanal restoring torce aching pe unt area
o a dezormed body is Callnd stress.
Stress Intena reatoring Force
inunal
Area et Cross Section A
T heL is no pemanent
change in the Configuraton
D the
he body, then he restoring torca is equa and
obpobite to the extenal deforming for applied
SI Unit -N/m Dimenaions - CMtlT-2]
TYpe ob Shress
1 Normal Stress/ Longitudinad Stress-
de
when a foxming torce acts normaly oves
an asRa of a bocy , then interna restoaing force set
up
up per unit a of the body Lallud normal Stress.
(a) Tensile Stress
I Hher
is an increas in he ungth or
extension o thu body in the direction of appliea
applied
force, hen h Ares set up is Calluc tensile stress.
Rigid Body- AA boduly s said to be rigid i. the relative
position o t s Constituent Particles remains unchanaed
when externad dejorming forces au applied to it.
The neasst approach o a rigid body is diamond or
Canborundum.
Actually no bedy is igid an eveH bocy Com
Com
be defovmed more or lis by he applicathon of suitable
force».
Irter adomic Forces
Tis the forcs between the atoms elue to elechostedic
interaction betwean he changes ob *he atoms.
Thesejorus ane eletrica in nawL and.ane actie
h the distance between the two ahms is o the order o
whun the two atoms ame
F
brought close to each othe
the distancea betwun thair
pobitivt nuclei anol electonn
louds et distubed and ro>
duu to his athrachve inter Attractio
aomic fov is poducud.
This authractive foru imcreases
U
with ducrease inr and beome
maximum at a Critical oistane
.8uond h i th athracive ro
tovce Stads dacreabin wi th
wther ducrease IMY.
, At a dtane . the irteratomic forca uill be zero anod
this distonu is Ccallud equlibium distanta.
hen the oitanu betweun two atoms fwther decreased
the indexatomic sforce. become repulsive and imcreases ith
decrease in Y.
TL
Th e Poten onesgs related with the interedomic force is
iven as
F:.
whn t h dis tncL betueun the two ato ms becomes Yo
becomes
the petential enugy t e Systm o t o aoms
enns
minimum and hunce he tuo atoms at sepahation To
ro
wil1 be in a state equiibnum,
i t h f u t h r decrese im r the ngahve valu ot hu
Potenial onunay decrea amd becomes zero ano than
atans postive valu with fuher eleerease in .
Intermolecudar Forces
It i the forcas bahwen the molecules due to ehcho
static interachion between he changes o t h e molecules.
Th fras ae also callud Vander waal fores
conel aA quite weak as Compasrd to inder-adomic jorcas
Fbrc betwtan two molecudes is gvun by
F Fat. + Frp
The valu ot Cmstants a anol b dupends upon thi Structure
Ond nahu o malecwes.
, Petential Enery Can be expressee a
U A
whna Yeprerts repulsive Conhibution and B
represends the athachve tonhibuion.
aEInteratomic forcas ahe So do loo times stronaer
than intermolecudan forcas
Elasticity
The propety o matter by virtue ob ohich a
bocdy tends to regain its orginal shabe and size a t e
the removal of dleforming forces s callud elasticity
Reason o Elasticity
A soid booy is Composed of atoms Or mole-
Cules. These atonms or mølecules a boumded tpaethe
by
by interatomie or intemolecuan forces and stay in stable.
euilibsam position.
when m exteanal force i applied to the body
hen rebtoring forces Come imto play olue to interatomic and
intesmoleculan fovces and bing he atoms to its
origma
position.
PentectyElasHe Body
The boy which pengectly regains its odignad
foTm om removimg he exteanal defor ming force, is
defined
as a perhectly elastic body.
EQuaste , Phobpher bronze etc
, Ptecty Plastte bocy
he, boey oloes mot have
any tendency to
recove its oiginal Com figwraton, on the removal ot
deforming force , then it is baid to be perhectly ebtie.
E. Putty, mud Paraffin wax etc.
Stress-
The inteanal restoring torce aching pe unt area
o a dezormed body is Callnd stress.
Stress Intena reatoring Force
inunal
Area et Cross Section A
T heL is no pemanent
change in the Configuraton
D the
he body, then he restoring torca is equa and
obpobite to the extenal deforming for applied
SI Unit -N/m Dimenaions - CMtlT-2]
TYpe ob Shress
1 Normal Stress/ Longitudinad Stress-
de
when a foxming torce acts normaly oves
an asRa of a bocy , then interna restoaing force set
up
up per unit a of the body Lallud normal Stress.
(a) Tensile Stress
I Hher
is an increas in he ungth or
extension o thu body in the direction of appliea
applied
force, hen h Ares set up is Calluc tensile stress.
