Variable Mass System | Rocket Propulsion | Chain Falling on Floor | JEE Physics | IIT JEE

[@mohitgoenka99]

🚀 Session PDF link - bit.ly/3DW2dU4 🔥 PHD SERIES PLAYLIST - bit.ly/3cQSxPT 🔥 GOLD Mine Link - bit.ly/2VhOGFF

[@saurabhkantmishra1796]

Sir electrostatic mai cavity ki question kerya do

[@saurabhkantmishra1796]

1 PhD series please sir

[@saurabhkantmishra1796]

Please sir

[@saurabhkantmishra1796]

Sir cavity per video banao ek

[@Stranger_is_back]

Really thank you so so so .... Much sir ❤️❤️❤️♾️♾️♾️♾️♾️♾️♾️

[@154bharshbhanushali9]

Mere Engineering ke second semester aagya vapas aapke video pe , ME101 course h 😅 ❤ from IIT GUWAHATI

[@dankkrrish6780]

Drop liya tha kya bhaiya aapne?

[@StudyFor_IITJEE]

dream college

[@mohta.]

1)thrust force, F = Vrel * dm/dt (6:30) 2) Rocket propulsion, v = u-gt +Vrel * ln(Mi/Mf) (11:00) 3) chain falling, F = 3Mgx/L (17:30) 4) Water coming out of pipe, F = pAv^2 (p-density,A-area,v-velocity) (19:35) 5) Thank you sir

[@mohitgoenka99]

well done dear #learnlikeneverbefore

[@siddhesh2703]

I can't thank you enough This phd series is so good and the topics are so unique no one literally teach them and skip them but these are very helpful thank you 🙏👍

[@mohitgoenka99]

You're very welcome dear. Make the best use

[@SovereignStream]

Sir phd series ke videos mains first attempt ke liye bhi dekhne hai ya bas revision videos are sufficient enough ?

[@balajiyadav4250]

Kitna aya 1st attempt me 😢

[@aparnajhariya3495]

​@@balajiyadav4250tu bata bhai

[@ronak3813]

ch*d gaye guru

[@Sm-ws8ji]

Konsa iit mila

[@NeelNitilShrivastava]

sir... for the rocket propulsion case you put "mg" in the eqnn directly but isnt the mass of the rocket changing so wouldnt mg also be changing with time

[@kailashanand5086]

yes! you are correct, the mass of rocket wll keep changing. however, what sir did is correct, and i'll try to explain why. so the equation that sir wrote, is at a random time t. it is a fixed instant in time (note: it is an instant of time and not a time interval). so for that particular instant in time, m is not changing!! so he just wrote the equation for a general time instant, and then integrated. hope that make sense

[@ThorFlix]

@@kailashanand5086 I have a doubt!! Sir derived the formula for thrust force when there was no external force. But, sir used the same formula in the case of ROCKET PROPULSION. I don't understand why it can can be used here since the momentum is not conserved.

[@unknowndev7051]

Underrated 💎 of physics. All concepts are clear sir. Lots of Thanku sir ❤❤

[@abmini448]

respcted sir plse make a PHD vdo on conservation of momentum & energy & mass. love u sir u r helping us alot

[@AyushShukla-zg6no]

Its easy only by practice we can command (if ur work energy topic is good)

[@ayushdey5494]

​@@AyushShukla-zg6noLaorets Juaraju

[@yuvrajsau]

amzing video sir .......... and using isro's rocket instead of any other rocket is cherry on top

[@SwarnabDas-rh8mq]

Ok so this is rocket science

[@kalpchajed8]

😂

[@AlishaDas-k7p]

😂

[@manishvaishnav821]

No, this not 0.0000000000000001 percent of rocket science.

[@AdarshSingh-gt2fk]

😂😂😂😂😂😂😂😅

[@garoutheherohunter8613]

​@@manishvaishnav821 We use tensor maths to deal with viscocity of air etc and curl maths etc this is not even the begining

[@physicsinfinitybyvadehrasi1608]

I suggest that you use vectors to make the direction of thrust force clear. Like the direction of relative velocity is downwards, say - ĵ and dm/dt is negative so that thrust force is directed upwards that is along ĵ

[@prakharpandey3083]

I saw this with 1.5x speed still I understand all things and attempt questions as well. Thank you so much for making ours concept crystal clear..

[@pravinpawar8033]

mast hai sir apke lectures they are really helpful

[@mohitgoenka99]

Glad to hear that

[@Yourcodehelper]

7:11 respect isro ❤️⭐

[@faisalahmadmir1225]

Bohat bura lagta hai jab itne ache content ko itne kam views hote hain.. I hope and I pray one day (soon) this channel will get views in millions..❤

[@Abhimanyu_BITSPilani]

I attended the same topic in an offline class in Kota yesterday & I can truly say that these 24mins are at par and better than my 1.5 hr lecture. Thank you so much Sir😊😊🙏🙏

[@mohitgoenka99]

Most welcome dear

[@v4explorers184]

very very helpful video, You are building confidence in so many students.. Good Job , Iam a mother of two IIT aspirant students, iam learning from u and teaching them. THanks a lot

[@mohitgoenka99]

It's my pleasure

[@abhijeetyadav9717]

2 min. Silence for aspirants who still don't know about this channel. 😀thank you for such amazing video sir.

[@mohitgoenka99]

My pleasure

[@learner3880]

Please provide session on PhD in 1.AC,RL,RC,RLC circuit 2. Block over block problem 3. Vertical circular motion 4. Circuit analysis. This lecture was amazing. I was able to understand everything. My these topics are only weak. If they get strong then mine physics would be done.

[@mohitgoenka99]

Block on Block - kzbin.info/www/bejne/opPQdaSunsqnZ80 AC-RL, RC, RLC - kzbin.info/www/bejne/bWXHhYxjpd-AldE

[@learner3880]

@@mohitgoenka99 Thank u sir. I was not knowing that it is been uploaded.😀

[@mohitgoenka99]

@@learner3880 its okay dear. I am here to guide you all

[@mahendra601]

Vertical circular motion is also explained in short in wpe one shot video that was not enough but u can go for it

[@pranavtejankar5947]

Thank You sir , I loved the way you explain the concept in detail . The topic of Rocket Propulsion🤩 was my weak part , but now with the help of this video I have cleared it and it's no more my weak one .

[@mohitgoenka99]

keep learning & solving #learnlikeneverbefore

[@Kpk476]

DOUBT..... IN ROCKET PROPULSION, that relative velocity of gas will be also be negative.. . Then wouldn't it overall become positive as dm/dt is also positive

[@RudraSingh-hmm]

ab kaha pe ho bhai? 1 saal hogaya

[@Kpk476]

@@RudraSingh-hmm IIT INDORE electrical

[@50_jaykumar95]

​@@Kpk476Congrats brother

[@Kpk476]

@@50_jaykumar95 wlcm bro

[@pratikgoswamiiitbombay8767]

Thank you sir concept crystal clear ho gaya ye vala

[@mohitgoenka99]

excellent

[@devidkonwar7736]

4:10 relative velocity always be addition of two velocity when both moving in opposite direction(Vr=Vgas+Vrocket). Let's apply in a practical situation: When you are in inside a car moving 100km/h, opposite car moving towards you with 100km/h, You will get to see opposite car seems to be moving with 200km/h towards you is the relative velocity.

[@thebravepirate]

Your dedication is superb!! 👏👏

[@mohitgoenka99]

Thank you so much 😀

[@akshatchoudhary8747]

9:14 sir why did you put -ve sign for Fthrust v relative is already -ve and dm/dt is also -ve so the Fthrust will +ve(upwards).

[@mayanksingh1262]

You are the best for physics No one is better then you at this level you know well what students need Great work♥️♥️

[@mohitgoenka99]

Thanks a ton

[@Dr.owaisAIIMS]

Fell in love with this SERIES 🔥❤️

[@mohitgoenka99]

Glad to know that dear

[@mehulgoyal7727]

9:17 But v(rel) is also negative, right?? 21:58 I know it won't have much effect on the answer but while calculating velocity of efflux(applying Bernoulli's theorem) why did we ignore the velocity of liquid at the top(as the area is given and is comparable)?? This will give the answer, a=200/999(very close)

[@ਅਭਿ]

✔ day 11 dhanwad ji

[@mayanksingh1262]

Simple and fantastic way of explanation ♥️♥️

[@mohitgoenka99]

Glad you liked it

[@TGRRohit]

at 9:08 v reletive bhi to negetive hai na sir

[@aarya8542]

Thank you very much for this crisp and extremely productive session !!

[@mohitgoenka99]

well done on completing it keep learning and solving

[@shashanktiwari4971]

Sir plzz make phd video of instantaneous axis of rotation

[@Stranger_is_back]

Thank you so much sir....♾️ ❤❤♥️❣️❣️❣️❣️❣️💗💗💗💗💓💓💓💓💓💓💖💖💖💖✨✨✨✨✨🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏♾️♾️♾️♾️♾️♾️♾️♾️♾️♾️♾️♾️♾️♾️♾️♾️♾️♾️♾️♾️

[@mohitgoenka99]

keep learning dear

[@vu2281]

Tq sir💖💖

[@mohitgoenka99]

most welcome dear

[@ringo4556]

Thankyou sir ye concept 1 year chod rakha tha ajj crystal cler ho gya thankyou so much sir ,pls PhD on RC circuit pls sir

[@mishrashivedra3357]

Thanku sir bahut acha laga be conti

[@madhavsingh9500]

Physics empire of Mohit goenka sir on youtube 👌 👍 🙌 😀 🙏 😊

[@mohitgoenka99]

👍

[@vinayakujjwal9029]

Respected sir please make a phd video on impulsive force covering all variations

[@how-about-no_56]

Sir you said F_thrust=(v_rel)(dm/dt)... here dm/dt is negative term, so F_thrust is negative, i.e. in left direction (as we assumed right side as +ve during momentum conservation), but you said F_thrust is towards right..why is that??

[@gopalmishra8441]

very imteresting sir ....phd series is quite helpful for jee advance

[@dakshrara6009]

in every explanation i could not understand how they write v rel and dm/dt , thank you for telling it patiently

[@mohitgoenka99]

#learnlikeneverbefore

[@PriyanshuDhami-ch1sj]

Thanks sir ❤️❤️ This series is much helpful for all JEE aspirants Sir please COLLISIONS mai v PHD video bnaiye sir

[@mohitgoenka99]

As soon as possible

[@kalpanagupta7884]

I am in allen and today is my test and I saw this video at 3am

[@mohitgoenka99]

well done dear keep learning

[@Ace-y7t]

Same but I'm watching this 4 days before my test

[@aarushbharadwaj3509]

I have Allen test tmrw

[@moviesmagic2664]

I don't have test now😂😂 Allenites...

[@jayeshb9323]

Phd series 😀😀very true sir ...thank you for the session absolutely loved it

[@mohitgoenka99]

Always welcome

[@V..Planet]

Timestamp 00:00 Why it is important for JEE Main too ? 00:30 Topics to be discussed in video 01:03 Derivation of Thrust Force expression 06:50 Rocket Propulsion Equation 11:13 Numerical on Rocket Propulsion 13:53 Chain Falling on Floor 17:39 Liquid Coming out of a Pipe/Vessel 20:40 Numerical on Liquid ejected from Vessel

[@J_Prince24]

Revision done ✅

[@mohitgoenka99]

well done dear keep going forward #learnlikeneverbefore

[@cricketdevotee9674]

Sir please upload more phd series video🙏🏼🙏🏼🙏🏼🙏🏼

[@RaushanKumar-lg9em]

Thanks sir for topic explaination. I was wondering on youtube from previous years to study physics topics wise. Please continue it sir and please upload 2-3 topics video in a day.🙏🙏🙏🙏🙏🙏🙏🙏🙏

[@mohitgoenka99]

I will try my best

[@theseusswore]

incredible video. understood the concept really well and in a really short amount of time !

[@satendrasingh9855]

Sir can you take PhD series on RC and RL circuits please

[@Atul_Tiwari1]

Sir please make a video on rotational dynamics.

[@pritampramanick282]

Ha sir thora bohut to confidence agaya

[@funnycatflick7115]

21:50 sir is question me Mass to decrease karega time ke sath to ye variable hua na , acceleration integration se karna padhega na???? sir please clear my doubt.....

[@mohitgoenka99]

the question is solved particularly for t=0

[@funnycatflick7115]

@@mohitgoenka99 got it Thank you sir

[@krupaallll]

sir i have doubt , in that chain falling problem how can we write v = (2gx)^1/2, because its not just falling under the gravity , thrust force is also acting on it which will depent on its velocity . when i wrote force equation for that falling chain it was like , xg - v^2 = L* dv/dt . is that correct ?

[@imaginaryworld946]

rotation and com revision done...💖💖(thankyou sir ji) charan sparsh

[@mohitgoenka99]

well done on completing it keep learning and solving

[@harshgarg2529]

Sir should I watch and prepare it for jee main or should do after mains because I have less time so I am doing topics for jee main only

[@rashmipriya9221]

Sir I didn't understand how thrust force is applied on the surface when the chain was falling ...... Because what I understood that thrust force is something that works more like a action reaction system

[@mohitgoenka99]

when chain falls, surface applied force on chain so chain also applied force on surface

[@arghadeep469]

Sir please PhD on oblique collision

[@mohitgoenka99]

noted dear

[@Realstylistic1845]

Excellent sir ♥️

[@mohitgoenka99]

keep learning #learnlikeneverbefore

[@NoMatterWhat279]

Sir @8:18 Why did you write net force =ma Bcoz as mass is changing,Why Is it not mdv/dt+vdm/dt=Fth-mg? Pls reply sir

[@mohitgoenka99]

in the previous slide we already derived that due to varying mass thrust force is Vrel*dm/dt. So in this one we simply used it.

[@kshitijvispute6792]

@Dheeraj, If you see it logically your eqn seems wrong as Fth and v.dm/dt would cancel out leaving behind a=-g…

[@kshitijvispute6792]

And if you’d want to see it conceptually… Just go by the basics.. use impulse momentum eqn: initial momentum+ impulse= final momentum you’ll get an eqn F.dt=m.dv -u.dm on simplification where F is external force(here gravity), just divide the eqn by dt and thus you’ll get F=ma-u.dm/dt.. and on putting F=mg a=u.dm/m.dt +g

[@tharlover554]

I don't know how to thank you sir ....... Love you sir..........

[@mohitgoenka99]

most welcome dear

[@kunalsharma-ez7pb]

Very nice class

[@mdsajidalam9324]

Bht shi se smjh aaya sir 😊😊

[@yuvrajshukla4616]

Sir please make a video on work energy theorem and consevation of energy when to use which theorem I am so confused

[@tharlover554]

Sir please also bring PhD series in rotation

[@sakshambhatnagar7386]

Jee thing is over Am back to u for 1st yr luv frm BITS Pilani ❤

[@Vedant_Bharatvasi]

Best series sir 👍😇thank you so much sir. Please continue it.... Hope you will complete mechanics soon.. 🙂

[@mohitgoenka99]

Keep watching

[@nidhipatil9537]

Formula 20:20 water coming out 6:21 formula thurst 10:43 equation

[@mohitgoenka99]

well done dear keep solving, learning and revising #learnlikeneverbefore

[@schiho9985]

sir how did you write F = m dv/dt in rocket propulsion shouldn't it be F = m dv/dt + v dm/dt

[@Jems-uo9ni]

Bhaiyaa COLLISION par ek video bana dijiye please 🙏❤️

[@motivationguru1689]

you the best teacher

[@thomas3146]

Love u dear mohit sir💗 Thank u x 3000

[@sarthak4632]

Sir please make revision vedio for fluid mechanics

[@mysticalpreacher941]

Make similar video on linear momentum conservation

[@rishabhyadav1003]

Very very helpful sir 🙏🙏

[@mohitgoenka99]

Keep watching

[@dipteshkp01]

sir these topicwise series is very helpfu.. please continue it

[@mohitgoenka99]

check our phd series playlist

[@laiba6139]

This was soo helpful. Thank you sir!!!!

[@mohitgoenka99]

Glad it was helpful!

[@chandanmaths1729]

Concept clear thankyou sir

[@dhruvgupta9530]

Ok!! now time for Doing PhD in COM variable mass 😎👍🏻

[@mohitgoenka99]

That's the plan!

[@mr.fahrenheit1420]

@@mohitgoenka99 sir phd in gauss law too 🤩🤩

[@jeeaspirant7210]

Loved it sir😍 U r great sir❤️

[@kailashkushwaha9296]

I love you sir and your dedication

[@srishtiagrahari4131]

Thanks a lot sir, your classes are very usefull for me

[@mohitgoenka99]

Glad to hear that

[@prabhun8106]

oh sir, you made variable mass concept so easy to understand as this was one of my leaving topics

[@mohitgoenka99]

Glad to hear that

[@letscrackit1065]

Thanks a ton sirji .

[@eagerbat3800]

Also Please make a video on Toppling .

[@payalthakur6065]

Thank mohit bhaiya

[@mohitgoenka99]

welcome dear. Make the best use

[@fnsjit733]

Ooh thnx sir.. this topic was skipped in schl.. the rocket propulsion part ..

[@mohitgoenka99]

welcome dear

[@RahulSharmaSingularity]

There should be e negative sign in the calculation of thrust force indicating its direction opposite to Force on ejected mass dm . good video !

[@LostZoro798]

Thank you sir very much for this wonderful lecture on variable mass system....I am preparing for jee advanced and I have completed hcv and moving on to some better books.. Sir can you Kindly suggest some good books.. I am 2026 aspirant.

[@weirdo992]

Do cengage and irodov

[@saurabhkunkulol6032]

Gained Confidence 👍 Thank you so much Sirji 🙏

[@mohitgoenka99]

Always welcome

[@aayushmishra48]

Love u sir... These are really helpful..

[@mohitgoenka99]

Glad to hear that

[@aayushmishra48]

@@mohitgoenka99 can't believe u r real and this humble.. U r my hero...

[@Sona-t8p]

love you sir dont ever end this channel!!!!!!!!

[@yasimrashidi4375]

EXCELLENT SIR

[@asifraza8298]

Bhaiya Fluid chapter pe phd karwaiye plz , selected questions karwadijye

[@AdityaSingh-oj4fg]

The most authentic video 😍

[@mohitgoenka99]

thnx for lovely comment dear

[@stusongdio9033]

Great sir ...as always!!

[@mohitgoenka99]

Thanks again!

[@RaushanKumar-lg9em]

Please provide 15 questions or more on particular topic sir.🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏

[@introvert__boy]

make phd on ydse plz ....

[@gaurav__5653]

Sir next video - circular motion pein and vertical circular motion mein