Equilibrium class 9 | conditions of equilibrium class 9 | 9th class physics | atifahmedofficial

Equilibrium class 9 | conditions of equilibrium class 9 | 9th class physics | atifahmedofficial
4.8 EQUILIBRIUM
Newton's first law of motion tells us that a body
continues its state of rest or of uniform motion in a straight
line if no resultant or net force acts on it. For example, a
book lying on a table or a picture hanging on a wall, are at
rest. The weight of the book acting downward is balanced
by the upward reaction of the table. Consider a log of
wood of weight w supported by ropes as shown in
figure 4.26. Here the weight w is balanced by the forces F1
and F pulling the log upward. In case of objects moving with 2
uniform velocity, the resultant force acting on them is zero. A
car moving with uniform velocity on a levelled road and an
aeroplane flying in the air with uniform velocity are the
examples of bodies in equilibrium.
A body is said to be in equilibrium if no net
force acts on it.
A body in equilibrium thus remains at rest or
moves with uniform velocity.
CONDITIONS FOR EQUILIBRIUM
In the above examples, we see that a body at rest
or in uniform motion is in equilibrium if the resultant force
acting on it is zero. For a body in equilibrium, it must
satisfy certain conditions. There are two conditions for a
body to be in equilibrium.
FIRST CONDITION FOR EQUILIBRIUM
A body is said to satisfy first condition for
equilibrium if the resultant of all the forces acting on it
is zero. Let n number of forces F , F , F ,
1 2 3
...........,F
n are
acting on a body such that
The symbol is a Greek letter called sigma used for
summation. Equation 4.9 is called the first condition for
The first condition for equilibrium can also be
stated in terms of x and y-components of the forces
acting on the body as:
A book lying on a table or a picture hanging on a wall, are
at rest and thus satisfy first condition for equilibrium. A
paratrooper coming down with terminal velocity
(constant velocity) also satisfies first condition for
equilibrium and is thus in equilibrium.
EXAMPLE 4.5
A block of weight 10 N is hanging through a cord
as shown in figure 4.29. Find the tension in the cord.
SOLUTION
Weight of the block w = 10 N
Tension in the cord T = ?
Applying first condition for equilibrium
There is no force acting along x-axis.
Thus, the tension in the cord is 10 N.
SECOND CONDITION FOR EQUILIBRIUM
First condition for equilibrium does not ensure
that a body is in equilibrium. This is clear from the
following example. Consider a body pulled by the
forces F1 and F2 as shown in figure 4.30(a). The two
forces are equal but opposite to each other. Both are
acting along the same line, hence their resultant will be
zero. According to the first condition, the bod
equilibrium. Now shift the location of the forces as shown
in figure 4.30(b). In this situation, the body is not in
equilibrium although the first condition for equilibrium is
still satisfied. It is because the body has the tendency to
rotate. This situation demands another condition for
equilibrium in addition to the first condition for
equilibrium. This is called second condition for
equilibrium. According to this, a body satisfies second
condition for equilibrium when the resultant torque acting
Most related searches
9th class physics chapter 4
9th class physics ch 4
9th class physics
9th physics chapter 4
9th physics ch 4
9th physics
physics class 9 chapter 4
physics class 9
physics 9th
matric part 1 physics
physics matric part 1
part 1 physics
physics part 1
physics matric part 1
physics matric part 1 chapter 4
physics matric part 1 ch 4
part 1 physics
part 1 physics chapter 4
9 class physics
9 class physics chapter 4
9 class physics ch 4
9 class
matric part 1
part 1 matric
physics
sindh board
kpk board
punjab board
all boards
Karachi board
by sir atif ahmad
atifahmadofficial
atif ahmad official
#physics
#class9
#9thclassphysics
#9thphysics
#matricpart1
#matricpart1physics
#matricphysicspart1
#atifahmadofficial
#sindhBoard
#urdu
#hindi
#freeonlineclasses
#onlinephysicslecture
#equilibrium
#conditionsofequilibrium
#introductiontoequilibrium

[@Abdurrehman-z1z]

Sir i have no words to explain your teaching method. Please sir ye raaz muje btawo itna confidence aap mai kaha se aya

[@sarimshah889]

Sir literally you really have an ability to transfer your knowledge to students

[@MaqsoodUlhassan-b1v]

Your hand writing and your drawings is very very very very very very very very very very nice 🙂👍🙂🙂👍

[@shahidkhursheed4529]

Man your board presentation is too good keep up the good work

[@atifahmadofficial]

Thanks 🙂

[@kinggamers558]

Your lecture help me to understand the physics very well Thank you so much

[@qariasumayya3471]

Yar freefire bhi khelte ho

[@arar931]

But anyways your Teaching method is very well done 👍👏❤️

[@MSaeed-ty7ql]

Sir ap se Samaj kr mujy yaad krny Ki zaroorat nhi parti bus ak bar pr lon tu yaad ho Gaya h❤thanku so much ❤

[@AlyasButt-cl4wh]

Kaya kamal drawing ha😮😮

[@irshadtahir7316]

best of =luck sir

[@therose6837]

Defienation 1 condition of equilibrium : "A body is said to satisfy first condition for equilibrium if the resultant of all forces acting on it is zero". F1+F2+F3..... +Fn. Defienation of second condition: "A body satisfy second condition of equilibrium when resultant torque acting on it is zero " Pie r =0.

[@atifahmadofficial]

Yes 🙂👍

[@therose6837]

@@atifahmadofficial 👍

[@Sadlife-x9y]

Thank you sir Your lectures help me to understanding the physics very well Again thanks Because of your deep explanation 🙂😂🙂

[@atifahmadofficial]

Welcome 🙂

[@kingAbdulllah0269]

You are very good sir and good lecture

[@Islami-h3p]

sir really you are perfect teacher for physics 😊

[@annaannashabanashraf6139]

Nice video

[@kinggamers558]

thank you so much sir your drawing is great

[@SahibKhan-un4ek]

Sir, agar frictional force aur applied force balance karte hai to car ko stop hona chahei pir ye uniform velocity k sath q move kar raha hai?

[@Zuhashehzadi-c9j]

Sir second condition for equilibrium long mein askta h ?

[@SafwanAhmad-h3c]

Thanks sir ,Allah, bless you❤

[@asianoureen24-fbasphdnasf16]

Your lecture is perfect because you are giving general examples other than book.

[@atifahmadofficial]

Thanks 🙂

[@fazalhaq4274]

thank u so much sir 💜

[@shahidaparveen4275]

Second condition for equlibrium ma torque zero kase ho ga

[@mashkoorhussain8389]

KOi jahl he tar a sawl he

[@afiabatool-xn9xy]

Simple when the turning effect of force is zero Or when the body is not in turning condition 😊

[@afiabatool-xn9xy]

Sir ap ne bola applied force or frictional force ek dosree ko cancel kr dee gi To phir car move kis force se kr rhii😊

[@KaramRehmanMalik295]

samee question brooo

[@danyalkhan-l1x]

I'm very inspired to your leacher😍😘😏

[@asadmehmood7673]

You did not explain the side informations. How net torque is zero in ladder and ceiling fan. Please explain these examples?

[@asadmehmood7673]

When a ceiling fan rotates which torque is produced clockwise, anticlockwise or both?

[@komailabdullahbrother8218]

Vvvvvvvvvvvery good explaining keep it up 👍

[@atifahmadofficial]

Thanks

[@arar931]

Sir ap numericals nahi karwatay ? ¿

[@MuhammadWaseem-hv2ci]

You are just brilliant sir

[@zafarwazir5210]

Sir very nice bahot acha

[@azanahmad9639]

Thanks Sir aap hamasha hi bohot acha parhata hn🥰👍

[@GalaxyOfKnowledge-w9z]

Thank you sir very informative lecture

[@syedasadm.naqvibukhari7189]

Nice sir 🙂

[@zill-e-humakhan6223]

If we provide a body a force more than its weight, then this body will move upward in opposite direction to the gravitational force. As time passes the velocity decreases because our provided force is decreasing due to gravitational force and air friction. At maximum height air friction becomes zero because body comes in rest and our provided force decreased and became equal to gravitational force and therefore sum of all forces becomes zero at the highest point. After a moment, gravity overcomes our provided force and the body starts to move downward in the direction of force. At rest, the acceleration was zero therefore body was in equilibrium. .......

[@mehmoodafzal.]

Bhot he pareH

[@atifahmadofficial]

Thanks

[@nehalshinwari3828]

Great sir 👍👍👍

[@asadmehmood7673]

When a ceiling fan rotates which torque produce clockwise, anticlockwise or both?

[@ZulfiqarAli-gt9vo]

sir ap ki drawing bohat zabardast ha MASHALLAH

[@atifahmadofficial]

Thanks 🙂

[@alibilal1100]

Sir can you explain simple harmonic motion by leaving comment. Simple harmonic motion occurs when net force is directly proportional to displacement from mean position and is always directed towards mean position

[@MaqsoodUlhassan-b1v]

You have deserve 2000000Million like ❤❤❤

[@MaqsoodUlhassan-b1v]

Your drawing is wow

[@mharis4830]

Sir your lecture improve my knowledge I have an exam tomorrow 😁🙂 by the way your lecture and presentation is great ☺️ excellent 👍

[@aroojfatima6243]

Well sir imma teacher and for every lesson I'm looking forward for your vedio lec....appreciate your work sir....

[@emanshah7132]

Thank you sir 😊

[@atifahmadofficial]

Welcome 🙂

[@shamsaabbasi7803]

MashaAllah good

[@kiranfatima7504]

Wowwwww. Thank you Sir

[@atifahmadofficial]

Welcome 🙂

[@arabiclecture]

This video is very helpful sir Kal Wednesday Mera final paper he mughay bohat acha samagh aya he ❤

[@Abdullah_Rauf786]

Paper too Mera bhi hai

[@shumailakareem766]

Amazing can't found words... for your amazing presentation and explanation😍

[@UsmanKhan-cm9gj]

The second condition is for dynamic equilibrium? Because when a body is at rest,i think there is no torque

[@atifahmadofficial]

Yes 🙂

[@MalikUmair-bi5pr]

Tomorrow is my exam your lecture is very helpful 😊pray for me

[@Saniafatima-ms1lr]

How was your exam?

[@merabzahra3244]

Your method od teaching is very well thanh you

[@Naeem-r3v]

👍👍

[@pushpendrapatel-ky1ti]

Very nice video sir

[@atifahmadofficial]

Thanks alot

[@takdeeraliali8669]

Thank you sir Sir your lectures help me to understanding as so easy Again thanks a lot sir And sir want to get notes after paying fees, but how?

[@atifahmadofficial]

Thanks 🙂

[@Rohbanagul]

Loved the video sir

[@atifahmadofficial]

Thanks alot 🙂👍

[@sherazali1458]

Which reaction force does the earth apply on body?

[@KaramRehmanMalik295]

normal force ig

[@zeeshansaadi94]

Thanks Sir G

[@SahibzadaHamidkhankhan]

tankyou very much sir

[@kingAbdulllah0269]

Thanks

[@MuhammadAbdullah12354]

In 2nd condition Torque produced by F1 and F2 are in Clockwise direction . Phr total torque zero kaisy hy.

[@irshadtahir7316]

nice sir

[@Munwar-l9i]

Nice

[@nabilatahira5631]

Sir thank you very much for your explained lecture. And your writting and drawing is very beautiful and teaching method is also very nice

[@nabilatahira5631]

Sir reply kerein

[@SyedZada-tg5st]

Well

[@muhammadhammad1706]

i have a question for you plz ap exampe bhi karwa diya kare

[@GamingWorld.9t]

Car drawing is op

[@TayyabaRizwan-q6r]

❤

[@zill-e-humakhan6223]

Sir is there any body in universe which is at rest but not in equillibrium???

[@atifahmadofficial]

A stone thrown up verticaly, at maximum height its Velocity is zero but it is not in equilibrium

[@zill-e-humakhan6223]

@@atifahmadofficial but jb ball kch seconds k lia rest krti he tu net force us time py zero hoti he tu equllibrium ki condition obey hoti

[@mzgraphy8475]

🎉nice

[@user-qt6zu9iv6i]

Thank you

[@user-qt6zu9iv6i]

My best teacher

[@sherazali1458]

In uniform velocity no net force act so why car move?

[@palestine693]

Look for eg u r driving a car 80km/hr after some time if u have covered the distance of 5km u check ur car speed which is still 80km/hr it means that u have covered the distance of 5km with same speed ie 80km/hr there no change in speed means so no change in velocity. If no change in velocity it is said that the car is moving with uniform (same) velocity . And if no change in velocity the acceleration is zero bcz acceleration is defined as the change in velocity in unit time . I HOPE U GOT IT !

[@palestine693]

So sum of all the forces ( no increase in force ie speed ) acting on body is zero the car is moving with uniform velocity ie no change in speed so no change in velocity

[@dua4704]

Amazing sir kamal kardiya apne ❤👌

[@HadiaRashid-g4n]

🎉

[@ShahzaibIjazShabi]

❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤

[@rizwanbugti8588]

TNx❤

[@Irfankhan-v6c]

Types of equilibrium pa Lecture da

[@MuhammadSaeed-jp7dn]

Thank you sir

[@bashirahmed7886]

Sir couple ki video ni mil Rahi he....ni bnaya he kia.......?

[@cakewaffle7418]

Thank you so much Sir 😇.

[@atifahmadofficial]

WELCOME 🙂

[@Zamin1119]

Sir torque ka sum zero kesa ho ga

[@saadfahid7364]

Second condition of equilbrium ka torque kasay 0 hoga

[@palestine693]

Sir kia car banai hai 👍👍💜

[@atifahmadofficial]

🙂👍

[@farheenishfaque5223]

Is ka numerical solve kerwa den

[@ifafsarosh7183]

Plzz make a video on numericals Tomorrow is my paper Aps student

[@aamirshehzad9736]

Olz notes