Work and Energy 02 | Energy | Kinetic Energy | Potential Energy | Class 9 | NCERT | Sprint

[@PW-Foundation]

📝Download Lecture Notes From PhysicsWallah App : bit.ly/2SHIPW6 🎯 Science group- t.me/joinchat/RYszj_1cAl8xEvnv 🎯 Social Science- t.me/joinchat/GCBE5bDgFdxrZeI8 🎯 Mathematics group- t.me/joinchat/GBbG4p5S_OVRV920 ----------------------------------------------------------------------------- 🗓️ Scheduled Syllabus For Sprint ( Class 9th ) released describing which topics will be taught for how many days. Available at PhysicsWallah App :bit.ly/2SHIPW6 •Duration:-1 month (Jan 2021 - Feb 2021) 🎉 Free Batch Exclusive on our KZbin Channel : Physics Wallah Foundation - 9 & 10 •Batch Details : 1) Best Faculties across India for different Subject/Topics. 2) Complete & Relevant Syllabus Coverage of Class 9th within 1 Month - Fastrack January 4,2021- February 15,2021 3) Monday - Saturday : Scheduled Classes everyday. •Physics : Tuesday, Saturday •Chemistry : Wednesday , Friday •Mathematics : Monday, Wednesday, Friday •Biology : Wednesday , Thursday , Saturday •S.ST : Tuesday, Thursday, Saturday, Sunday 4) Scheduled Syllabus released describing which topics will be taught for how many days. Available at PhysicsWallah App :bit.ly/2SHIPW6 ----------------------------------------------------------------------------- OUR SOCIAL MEDIA PROFILES : ⭐Instagram Handle : instagram.com/physicswallah/ ⭐Facebook Page: facebook.com/physicswallah ⭐Twitter Account : twitter.com/PhysicswallahAP?s=20 ⭐ PW App on Google Play Store : bit.ly/2SHIPW6 ❤️ Padhai Karte Rahe, All The Very Best 👍

[@abhirajpratap9141]

Hiii

[@mrpanda2498]

In concept Building question no.2 minus isliye laga hai kiyu ki wo body ko rok raha and displacement and force in opposite directions me hai.

[@ayushparkash152]

Because he want to ✋object it can't displace the object but object can't change its direction so it is negative

[@ayushparkash152]

Is it ✅ or not

[@videoworld7078]

Gajab

[@sprihagaur]

26:29 ~ To stop the object, the force applied is in the opposite direction of object moving which creates a 180 degree angle, making the workdone negative.

[@Abhishekyadav-wk8ol]

You are right. Good

[@vanshyadav1646]

I am also right

[@indianeducationzone3176]

Same

[@NayakAyash-he5on]

Well bro

[@nirupamananda9234]

Correct🎉

[@shreemiyaduvanshi1811]

26:19 workdone came negative because the force applied on the object to stop it was in the opposite direction to the displacement of the object. THANK YOU VERY MUCH SIR! Your explanations are great.

[@himanshusingh-B]

correct

[@raksha958]

Sahi h

[@abishugupata625]

yes

[@starlab5296]

Yes

[@alwinsjoy6961]

​@@abhigyanmishra9438 When breaks are applied to stop a moving vehicle, the force acts in the opposite direction of displacement, So we take the work done as Negative

[@HeadPSKAZIM]

1.) 1/2* m/v² 2.) when object ready to fall it energy is "mgh" and as it fall it's potential energy convert into kinetic energy and increase in kinetic energy in increasing in it's velocity. When object touch the ground it's kinetic energy is in higher level and when object stops it's kinetic energy is become zero 3.) Yes ,an object on ground so it is not in motion so the kinetic energy is zero and object height from ground is zero so it's potential energy become zero and and sum of potential and kinetic energy is mechanical energy as both energy is zero mechanical is zero so every point of energy seen is zero

[@callipainting761]

I didn't know about this channel my sister told me about this channel and from that time I forgot all the other u tube channels 🤣😂😂

[@Gamer-fd1kv]

Same bro

[@imperfect7443]

Etna jhut or chut hazam nahi hota hai

[@rajnishagarwal1448]

Same pinch 😂😂

[@radhikagoyal8453]

Literally yes

[@pradiptakumarkar4488]

Same here

[@byomthakur3374]

Challengers 1)-mv²/2 2) Becomes zero 3) Because ground is considered zero level and pot energy = mass * g * height from ground and when object is placed on ground h = 0 So, mgh = m * g * 0 = 0

[@Aryan725_]

U r write 👍👍

[@sportslovers1462]

Superb anwers dear

[@byomthakur3374]

@@sportslovers1462 THANKS BRO

[@Shivhari_calisthenics]

@@byomthakur3374 Q2 Brother if an object freely falling then it potential energy transferred to kinetic energy along height Then it's completely comes in rest (on ground) then it's totally mgh becomes zero converted to kinetic energy. So , the object when reached on ground then it all mgh becomes ke. So , it's have kinetic energy, Not zero

[@subhashrana8073]

2nd and 3rd answers are wrong kinetic energy is highest at ground

[@the_real_prabhat]

26:20 , Sir..for example, Displacement right me tha, usko rokne ke liye force left me lagaya.. Toh dono ke bich ka angle 180° bann gaya.. And formula = F × s × cos. And Cos180 = -1 So, Answer negative me aaya 👍👍

[@amritayadav1035]

Hw ans is 1- an object moving with constant velocity if we aply the force opposite of it then it come to rest then work done is negative 2- it's kinetic energy convert into heat energy and sound energy and also potential energy because it shape change due to collapse to earth. Because of these it produce sounds. 3- no

[@manishsinghmk9893]

Good

[@rishighuriyani23]

Because we have stop the the body so we applied the force in the opposite direction the angle will be 180 so the answer will be in negative cos180 = -1

[@yashhjaiswall]

9:11 Sir, I was thinking about this method only but you are great and a legend in our term.

[@abhajha9311]

26:31 The work done is negative because when we apply force to stop the ball it's make a 180 degree and we know 180 degree is a part of negetive workdone.

[@pratyhuhs]

Work done is never negative. It's always an absolute (positive) quantity.

[@souravkumar9058]

26:33 Work done is negative because the force is applied to stop the body and it's opposite direction ❤️

[@mtsindiangamerz]

Yes 🙋

[@opp4ushorts_1]

You are right but we can say angle between force and displacement is 180°

[@ArnavSingh-go8pq]

The force acting to stop the object is friction force that is in opposite direction that' s why it is negative

[@shabnam1071]

27:10 Workdone is 4mv square And per cent is 800 percent... Sir u teaches the best 👌....

[@sushiladevi2041]

Correct...

[@ojas.0012]

Niceeee

[@ansh.sharma3926]

Absolutely right👍

[@rinkaaazdssigarg3169]

(Final -initial /initial )×100

[@sobansingh7465]

Work done is negative because force is acting oposite side of displacement... You are best teacher of physics love from uttrakhand

[@sanjananegi1872]

I am also from uttrakhand

[@rajivnagar02haldwanirural11]

Me also ....aa Chu ham pahadhi ...😌

[@Officalvegeta749]

Go watch alakh sir`s videos

[@_lifestyleofshreya_]

king of physics @rakshaksir salute to the way of teaching and craking funny jokes in between make me smile everytime.... THANK YOU SIR

[@BR.ESPORT18]

Hii

[@arya3692]

Challenger questions : 1.) Workdone =-1/2mv^2. 2.) K.E=0 3.) It has no energy because it is on ground and it is taken as a reference point and also it is not moving...

[@sarthakgautam_]

50:17 yes sir you are right we apply force in upward direction we just decrease the amount of applied force in the upward direction.

[@PriyankaSharma-kz5xy]

26:25 jab bhi force aur displacement opposite direction mein hote hain , tab workdone negative ho jata hai

[@odeus...3857]

Sir Work done is negative because the Force applied and the displacement that took place were in opposite direction and formed an angle of 180° . Now the value of cos theta 180° is -1 and Work = Force x Disp. x cos theta That is why work done is negative and it also means that it is a retarding motion.

[@anonymous-sm6sh]

32:50 😂😂 26:23 Because the work is negative work and thetha is 180 degree and force is acting in opposite of displacement 28:00 sir answer is 800% Challenger question 1. -1/2 mv² 2. When object comes in contact with ground .energy conversion happens . Like sound energy , heat energy etc 3. No sir , If object is at rest on ground . Clearly it has KE,P.E(due to height) =0 . But sir the object can posses other forms of energy as well like P.E(due to configuration ) and also solar energy , wind energy , electric energy. Hence Energy =(not ) 0 .

[@pearl_yyy]

2nd wale me pucha hai uske K.E kya hogi

[@2027iisc]

@@pearl_yyy usme pucha hai ki uski kinetic energy ka kya ho jayega answer is ki uski kinetic energy sound heat and all me change ho jayegi

[@Krizzjain-_-31]

1.If force and displacement are in opposite direction, workdone called negetive 2. Angel between force and displacement is 180° 3. It will increase the speed (RETARDATION) 26:28

[@aditi7346]

26:33 workdone is negative since the force is applied to stop the object that is the force applied would be on the opposite direction than that of the displacement .. Hence , the workdone would be negative..

[@poonamkitchens]

BTS ARMY!!!

[@aditi7346]

@@poonamkitchens Yep!💜😁

[@aditi7346]

@@poonamkitchens Hbu?

[@swaritrai4995]

You're absolutely correct

[@renurathore5489]

Are u an army ⟬⟭💜

[@Ravager-wb1rd]

Too good man...idk what to say....u r the only teacher with whom I can read physics with intrest 46 Reply Too good man...idk what to say....u r the only teacher with whom I can read physics with intrest 46 Reply Too good man...idk what to say....u r the only teacher with whom I can read physics with intrest 46 Reply Too good man...idk what to say....u r the only teacher with whom I can read physics with intrest 46 Reply Too good man...idk what to say....u r the only teacher with whom I can read physics with intrest 46 Reply Too good man...idk what to say....u r the only teacher with whom I can read physics with intrest 46 Reply

[@anshikaverma2680]

26:28 because we have to stop the particle and the angle between them is 180° and Cos 180° = -1

[@bhanuvlogs4593]

Who is watching this in 2024 😅

[@AdityaSharma18383]

Me

[@_Play_With_Avd_]

I am watching in 2112😅

[@sampurnabiswas4102]

Me

[@arunPrasad-kv9zt]

Me

[@AbhishekOjha-r8t]

Me😊

[@krishnakaushal8834]

Q1 - K.E Q2. Its K.E ----》P.E Q3. If the object h=0 from the ground and it is at rest so the. P.E + K.E. = Zero. And sir i have a doubt if we are in space so then also the object should have the P.E . And sir class is awesome 👌

[@LeviAckerman-xk4xg]

Yes I also have that question

[@mrinalsahu5713]

@@LeviAckerman-xk4xg IDK much ( i m also a 9th grade student ) Just sharing my POV ( do research by ur own , my POV can be wrong also , i m not responsible if u get less scores ). PE needs a relative level ground to calculate . AND in gravitation it says every mass attracts to each other . So in space there will be at least something to relate ( for example moon/satellite is relative to earth ) by gravity . So, we can find the height for displacement . Here is the definition of PE :- the quantity determining the energy of mass in a gravitational field or of charge in an electric field ( copied from google ). OR simply a stored energy which defines how much energy it will use to perform a certain displacement … since displacement is a vector quantity it needs a two relative points . The object will have PE accordingly .

[@mrinalsahu5713]

@Technoblade rest in peace 9 mahine pehle likha tha .... ab toh mujhe bhi samajh nhi aa rhaa🤦‍♂🤦‍♂😅😅...basically relativity ka khel hai....agar koi cheez space me hai toh uska mass..aur baki falna calculate karne ke liye ek relative matter chahiye... so potential energy uske hisaab se lagega.....deep space me shayad hi minute figures honge pr wo zero nhi hoga...kyonki space actually me bhara hua hai..........mai galat bhi ho osaqta hoon teacher /proff se consult kar lijiyega

[@Pragati_23]

Sir negative isliye aaega kyuki apn force lga rhe displacement ke against or angle bhi hoga 180degree isliye wd negative hoga...

[@visheshrattan699]

%age change in kinetic energy = final K.E -Initial K.E /Initial K.E ×100

[@Devang360]

No i thik u are confused btw 2 formula of delta kinetic energy and formula to convert energy in percent

[@arvindthakur2506]

Sir literally aap se physics padh ke bahut Maza aata hai aur har ek concepts ek hi baar Mai mind Mai set ho jaate hai. I'm you're great fan Sir ji.

[@siddharth7434]

26:24 because the direction of force and displacement is opposite

[@aliabbas4122]

Sir really l have seen so many teachers...but no one is like you.... really you are the best teacher...

[@gamesinblood7167]

Ans- 1) -1/2mv square 2) It becomes zero. 3) Yes, Because the ground is considered as a reference point which is equal to 0

[@sachinmehta8564]

Sir you are amazing teacher of physics there is no sir like you.

[@parasdhiman5001]

-1125 J because the let object was moving(displacing) right side and we have to apply left side force (-1125 J WD) then the object will stop. Angle between them is 180 degree so negative WD

[@harshvardhanpate913]

Question Number 2 work done is negative because the object displace forward and force is in opposite directions .So we know that when force and displacement are in opposite direction then there is negative work done and create angle of 180 degree.

[@powerofpositivethoughts3188]

So nice lecture sir , love you sir , sir aap Jaan ho hamari , thank you so much sir , aap ki bahot help mil rahi hai , sir aap God gift ho sabke liye , sir all India apke sath hai , thank you sir from all India🙏

[@onepenonetab6663]

right bhai

[@abhimanyukumar4552]

Humko padi mai nhi lagta ke karu

[@AshishKumar-x8f3t]

Initial workdone on the body is 1125j and the final workdone on it is -1125j as the force is in the opposite direction as that of displacement

[@pranavmaheshwari3152]

I am studying this chapter again bcoz of class 11th and sir's lecture is super great op

[@AkashSingh-lj7ow]

26:30 because in this case angle formed force and displacement is 180°🙏🙏

[@nileshgarg4599]

Ohh bhai sahab OP 🔥🔥

[@AkashSingh-lj7ow]

@@nileshgarg4599 kya op bhai

[@sciencestudy2188]

2-the PE that convert into KE is remain store in the obj according to its Height (Matlab PE is equal to the h of obj from the ground so when we fall it it's KE = to the PE and PE equal to the H of obj so, Jo PE he vo remain reh jae gi obj kyoki vo to KE change hue hi niii due to stop before touching the ground

[@aryanmittal1325]

Sir please explain Relationship between kinetic energy and momentum.

[@atharvapratap4462]

Increase in kinetic energy would increase the momentum of a body and decrease in kinetic energy would decrease the momentum of body

[@ourtargetf1283]

01:03:12 question 3. Yes the energy will be zero because of we know that kE=1/2mv^2 -1/2mu^2 and body is in rest. And there is no displacement.

[@RajeshSingh-hy8kp]

1- in order to bring the object to rest the work done must be equal to K.E of moving object =1\2 MV square 3- yes

[@puspanjalimishra7943]

1)- the energy required to stop the object is -1/2*m*v^2. 2)- its all kinetic energy is converted into it's potential energy that follows the conservation of energy as sir will explain this topic on next lecture. 3)- yes, object placed on ground have zero energy because as our reference point is ground at zero level the height is zero so potential energy of an object is zero because of it's height which is zero. Hope it helps.

[@rajaramsingh4492]

Hloo

[@priyankamehrotra.4409]

Too good man...idk what to say....u r the only teacher with whom I can read physics with intrest

[@AjayKumar-jr7vl]

Yes you are right

[@vishubhai7495]

Yes u are right 💯

[@manishsinghmk9893]

Hlo

[@infinitygaming7331]

No ur wrong😎

[@Krish0012]

workdone came negative because the force applied on the object to stop it was in the opposite direction to the displacement of the object. THANK YOU VERY MUCH SIR! Your explanations are great.

[@tutugamer436]

Thanku

[@rishi8997]

49:42 sir hum smuggling nahi karte 😉

[@rajvinderkour2213]

Sir you made my life so easy and make the physics enjoyable ❤you are amazing 👏 👏 ❤ I really like your teaching style you are mindbolwing sir 🎉

[@lavanykandwal1817]

26:24 Work done is negative because the work is trying to stop the mass and to stop, we need to apply force in the opposite direction of the displacement which means angle between force and displacement is 180⁰ which hence means work done is negative .

[@lovelysrivastava3243]

1xactly

[@anugrahmishra1517]

Change in kinetic energy is 4MV^2 and percentage change is 800%

[@RakeshKumar-en2gl]

Homework questions (i) W= -1/2.m.v.v (ii)When the body comes to the ground it's final velocity becomes 0.then,when the object it at rest it's kinetic energy is 0. (iii) If a object at ground and if it's final velocity is 0 then it's kinetic energy is 0 or it's final velocity is non zero then it's kinetic energy is non zero. Thank you so much sir for the best explanation.My all concepts are clear😊😊😊😊thanx again😊😊😊🎉🎉🎉❤❤❤

[@Raghav_Tiwari]

Challenger Answers - 1. - 1/2mv^2 2. When an object falls on the ground with some kinetic energy , it never stops frequently. It rolls upto some distance in which its remaining kinetic energy is transformed. 3. It depends upon the reference point , if I had taken ground as the zero point and the object is experiencing no motion then there will be no energy in that object.

[@unikkickgaming8330]

Thanks ❤️ bro

[@paramveergurjar469]

Sir I have an question : Is change in kinetic energy is equal to change in potential energy. MGHf - MGHi = Work done 1/2mv^2 - 1/2mu^2 = Work done Both RHS is same.

[@shiyadm2591]

Concept : 2, In the work done the force we apply is in a direction but the displacement is in opposite direction, so the object decreases it's speed and becomes zero velocity and that is the negative work

[@mahreenfatima6883]

Tomorrow is my exam I don't know how my paper of physics gone but when I find your channel now I understood all topics of chapter work power Energy thank you sir ❤️❤️❤️

[@rajkumarwagh9293]

😮

[@alka1699]

Work done is negative because the the direction of force was opposite to the direction of Displacement and the angle formed between is 180°. Another reason: Here the kinetic energy is decreasing that is why work done is negative.. Because work done is equal to the change in kinetic energy. Thanks a lot sir.. You have a great experience of teaching..🤠🤠

[@PriyanshuPatel-d5d]

work done in negative because the body displaced straight direction when applied force in different direction for making body stationary then it make cos 180 which value is -1 that's why work is in negative ... like you like answer ❣❣❣

[@marklexluthor6603]

In Concept Building question 2, Work done was negative because the angle between the force and the displacement was 180° and cos 180°= -1, you taught us about this in the first lecture

[@mohitsingh9a542]

Sir your explanation is very perfect i understand this chapter very easily thank you so much sir

[@adiko357]

Concept building ques.2 The workdone is -1125 because we are applying the force in opposite direction of displacement so the angle will form 180° and 180° is the negative work so workdone is -1125. Thank you And sir you teach very nice😍

[@blackninjagaming5423]

Sir kyunki displacement" s "toh aage ja rha hai and jo force hai use rokne ke liye woh piche lg rhi h means retard kr rhi hai toh Wd = Fscos theta se jo angle bn rha h 180 degree ka h and cos 180 = -1 hota h toh WD negative m ajayega

[@noobgamer4103]

Yes

[@dharmendrabhardwaj323]

Q1 = -1/2 mv² Q2 = converted into sound, heat & other forms of energy Q3 = yes has H = O and V = 0

[@naturegreenscape2741]

2.kinetic energy change into potential energy

[@dharmendrabhardwaj323]

Ground level = H = 0 Potential energy = 0

[@justawolfwithinternetacces9177]

@@naturegreenscape2741 When an object falls freely, its potential energy gets converted into kinetic energy and when the object hits the ground its kinetic energy gets converted into heat energy and sound energy

[@alyeeniftikhar7224]

Challengers Answer 1)-mv²/2 2) KE = !/2mv^2 here on collision v = 0, therefore KE = 0 but we known energy could not be destroyed. So, it would be converted into heat and sound energy 3) Because ground is considered zero level and potential energy = mass * g * height from ground and when object is placed on ground h = 0 So, mgh = m * g * 0 = 0 Love from kashmir ❤❤❤❤

[@shreyashrivastava1055]

26:29 when force and energy are are in opposite directions....and the angle between them is 180°, then work done will be -ve

[@RishavPlayz2007]

cos theta becomes -1

[@manishsinghmk9893]

Good

[@neelamsahu8826]

Challenger Questions Answers 1) -1/2 m v^2 2) because the collision of earth and object is inelastic collision therefore kinetic energy gets converted into heat and sound energy 3) It does not have zero energy because it has Gravitational potentional energy(U)=-GMm/r

[@childsinginggroupcsg4035]

3) it has zero kinetic energy and zero potential energy as force is acting on it but it has no displacement

[@bablukumarsingh2955]

@@childsinginggroupcsg4035 yep.. your answer is correct

[@infinitegamer1747]

Sir you are teching us like a legend............ Next level Explanation❤

[@kindnessgamer2388]

🖖🖐🖐🖐🖐

[@arimasrivastava-10b76]

Sir, in the last challenger question of L1, why are we calculating the work done by force of friction by multiplying -5 and 10 because work done is calculated only in the direction of force applied although in this case displacement is not in the direction of frictional force

[@ayushsinghrawat5980]

Workdone is of three types negetive positive or zero. Watch the previous lesson again for proper understanding.

[@Anwesha01]

26:26 Sir! Jahan se stop krenge uss place ka angle aur object ka position ka angle 180° form krega as dono ke direction opposite h, that's why!

[@krishna290gamer2]

Challengers:- 1. 1/2 * mv² 2. The KE will be absorbed by the ground. It will move it's molecules and will boost their sleed but it will be very less. 3. Depends, if the object is made up of matter then it's particles will have KE and if we choose different grounds then its PE will not be equal to 0

[@Ayush.7841]

First wala -ve hoga

[@protagonistmemer7718]

2 wala galat hai

[@protagonistmemer7718]

3 wala bhi galat hai

[@akpro4666]

Hats off to you sir ❤️ Thank you soo much for putting so much effects to teach us ❤️ 😊

[@football-lover.7]

26:29 Because we need to stop a body so final velocity = 0. U = 1125 And when we subtract v-u so we get negative workdone

[@danceclassdc9824]

26:26 work down is negative because we are stopping train

[@factoboy1295]

The only thing I want to say is - "Best video ever 🔥🔥🔥🔥" salute you sir

[@jagyannarayanpati7069]

because angle between f and s is 180 degree

[@uditanshukumar120]

Negative because we applying force in the opposite direction of the displacement

[@gauravhere1832]

👍👍

[@leyla_tv16393]

So sad that I can’t understand the language but he had clearly explanation, love you teacher 👨‍🏫

[@noobgamer4103]

Why?

[@aryanhoque6944]

Are u deaf ?

[@SayantanEditx]

Workdone will be negative as it will decrease the speed(redarded) and angle between F and S is 180° 26:29

[@akshatbharakatia9282]

Because when we stop body we apply force in opposite direction of displacment of body so the angle between force applied and displacment done by body is pi and value of cos pi is -1

[@mohammadamanatalikhan]

sir thank you soo much for this wonderful lecture

[@nirbhaysingh4232]

There is negative work done because velocity has decreased

[@vaibhavgupta8814]

Very nice exaplaination sir This is very helpful video 🙏

[@freefire_official__8055]

Wd is ve- cause angle b/w force and displacement is 180⁰

[@rekhadubey8745]

The workdone came in negative because to stop that object person had to apply force against displacement so the angle between force and displacement would be 180 degree .

[@aavishisingh3032]

yes the force and displacement is in also different directions so angle them between them is 180'

[@kavyak3748]

FOR STOPPING THE BODY WE HAVE TO APPLY FORCE IN OPP DIRECTION SO THE WORKDONE IS NEGATIVE

[@AjaykumarSingh-cz3ty]

Hyy

[@surendrayadav9535]

Force and displacement are opposite direction so workdone is negative 26:34

[@iayt2284]

41:45 Sir,In case if we are applying same force as earth then it will termed as balanced force and balanced force can't produce acceleration, then how is it possible to lift that object...🤔😊

[@fakihatariq9149]

Balance force does not produce acceleration but it can produce uniform velocity😂😂

[@snehatallapu]

You need to know first law of motion for answer

[@Sahil-ot8uo]

Sir apke padhane ki wagha se mere physics me full marks aaye haim😊

[@cry_csgo]

Work done is negative because resistive force is applied and thus angle between force and body’s displacement will be 180 degree

[@ayushraj3575]

Sir , if a body is at rest ,it has zero kinetic energy.a train which is in motion it will have kinetic energy,but with reference to another train which is moving parallel and with equal constant velocity ,both of them will be at rest with reference to each other,in this case will kE will be zero?

[@pankhurisworld8341]

Very good beta

[@ayushraj3575]

@@pankhurisworld8341 mind your language

[@CommerceKaur599]

40:03 😂 " Bccho karvayi to workdone se hi start hoti hai " 😂 Hats off to u sir ❤️

[@PriyankaSharma-kz5xy]

28:11 q3 delta KE = 4mv² % change = 800%

[@kushagrakatare]

Q1. By the use of work energy theorem it can be done answer is -1/2mv^2. -ve as it is in the opposite direction of the Motion of the object Q2. It's kinetic energy changes to the sound and heat energy while hitting the ground while the total energy remains conserved Q3. No it has the internal energy of its body due to chemical reaction taking place inside the body (respiration)

[@kushagrakatare]

Challenger questions

[@kushagrakatare]

@@anonymous-sm6sh kya galat hai answer mein bro

[@sanskarkumar464]

Can someone please explain to me how Is downward force the same as gravity? At 50:56 sir said that it will take the same amount of force to displace the object downwards as it took to displace the object upwards. I mean, if it took me to lift a 6 kg object with 10 newtons of force upwards, to bring it down, it should take less than 10 N of force.

[@YashKumar-zd9sj]

If you apply force less than (mg) there will a sudden displacement of the object downwards.... To avoid that we should take force equal to (mg) .. ...Correct me if you get a real solution for this...

[@prithviraj-r9f]

@@YashKumar-zd9sj aukat mein

[@sunnyverma6620]

Kyunki body jo hai vah Aage Ki Taraf travel kar rahi hai usko Hamen rokane ke liye Piche ki taraf khinchna padega Jo UN donon force ka angle Hoga angle between force is 180 degree so work done is negative

[@kshatriyaParth]

26:23 Answer, because of retardation force. Force is one direction and displacement in opposite direction

[@DrOtaku112]

Yes

[@amishchaudhary9765]

sir olympiad level question 1st bar mai sahi aya without help thanks sir :)

[@jankiramanjha]

Q-2: It is because force is applied in the opposite direction of displacement .

[@user-iz5uc5vq1c]

Sir kya padha reh ho aap ... seriously I can't describe you in comment section... seriously..I wish that you teach us ... chemistry or bio too....sir ..I am so satisfied to see your lacture... thanks sir ...

[@proveenkumargupta4661]

Sir mujhe sirf aapki class me maza aata h ...

[@aashukinra2868]

Doubt:- The SI unit of workdone is NM And the Si unit of energy is MV. NM not necessarily be equal to Nv but why both of them are equal to joule?