Class 11 Physics | Rigid Body Dynamics | #38 Example-19 on Rotational Motion | For JEE & NEET

PG Concept Video | Rigid Body Dynamics | Example-19 on Rotational Motion by Ashish Arora
Students can watch all concept videos of class 11 Rigid Body Dynamics for jee & neet in proper sequence through PG channel playlist. Click the link below to watch all videos of Rigid Body Dynamics--
• Class 11 Physics | Rig...
On Physics Galaxy website www.physicsgala... you can learn physics through complete Physics Video Lectures for IIT JEE by Ashish Arora. This is the most comprehensive website on Physics covering all the topics in detail. No wonder, in its trial run itself, this one of its kind website topped the world ranking on Physics learning.
To keep yourself updated about physics galaxy activities on regular basis follow the facebook page of physics galaxy at / physicsgalaxy74
JEE & NEET aspirants can post their doubts on Physics Galaxy doubtX forum for their preparation on doubtX portal doubtx.physics...
Students can follow Physics Galaxy series of books for NEET, JEE Mains and JEE Advanced preparation. Content of these books, students can browse and order at edyapp.com/phys...
For next video click on
• Class 11 Physics | Rig...
#physicsgalaxy #pgconceptvideos #RigidBodyDynamics

[@soumyadeepmandal5624]

Sir how the angular impulse is Jh??

[@physicsgalaxyworld]

Angular impulse is the product of applied torque and the time at the time of impulse... here if J = F.dt then angular impulse will be given as Fh. dt = J.h

[@soumyadeepmandal5624]

Got it Thank you very much sir

[@ArunKumar-dv8zw]

@@physicsgalaxyworld Sir I am obviously very late asking it, but a doubt has been troubling me a lot. How is torque equal to F.h here? I thought in rolling motion the sphere rotates about the point of contact with the ground, so shouldn't we take distance from ground instead of center of mass? i.e. R+h instead of h?

[@madihasiddiqui4540]

@@ArunKumar-dv8zw no Actually it rotates about its Centre of mass not about point of contact

[@ArunKumar-dv8zw]

@@madihasiddiqui4540 I got my doubt cleared haha. I was actually missing the obvious fact that changing the point where we are taking torque changes the moment of inertia accordingly. But it does rotate about the point of contact. Just take the perpendiculars on all the velocities of the particles of the rolling object, and you'll find that the instantaneous axis of rotation is the point of contact.

[@avantika505]

Sir are we ignoring friction here? Isnt friction required for body to start rolling? Or is it not needed here because only J can make the body roll?

[@alphaiitd1]

Thanks sir

[@tarachand1256]

What is the use of rough surface then

[@tarachand1256]

Sir plz help me in this and my previous doubts

[@tarachand1256]

Sir plz help me in this and my previous doubt s

[@shashikantmaurya1038]

@@tarachand1256 to confuse ovio ..as its said does nt slip so the minimum condition will be to attain pure rolling from begining only as the impulse is supportive to linear as well as angular velocity

[@snehabalakrishnan9516]

Sir can we solve this using other methods..

[@alexs6284]

thanks :)

[@kondraguntasurya9684]

sir these videos is sufficient for jee adv?

[@RishabhSharma-ho5dq]

Sir why did we took jh ???? As it is at a distance r from centre??? Please help sir!!!

[@FitnessFreak]

irodov question

[@manikmehta2727]

Sir why Normal reaction is not mentioned and if done by Normal reaction method then we have to take impulse by normal perpendicular to surface..

[@uditjec8587]

Sir, shell is in rotation with translation then why you are taking angular impulse about centre of shell why not about the point on the ground? Please clarify sir

[@surya8891]

a rod of length l forming an angle theta with the horizontal strikes a frictionless floor at A WITH ITS CENTRE of mass vnot and no angular velocity.assuming that impact at a is perfectly elastic find angular velocity of rod immediately after impact.

[@physicsgalaxyworld]

Use energy conservation and equation of coefficient of restitution at the point of impact... and solve these equations...

[@srihariks6693]

sir I am not answered for my questions for more than 5 months ...?????

[@mr.comicalbanda8260]

sir I am bit confused regarding that, L=Iw is used for body in pure rotation, but here body will perform general motion, so how can we use L=Iw? please reply

[@sarth6430]

watch the concept video on angular momentum, and see the part where case 4 is being discussed.

[@mehbubahmed7973]

sir can it be done by conserving angular momentum

[@physicsgalaxyworld]

Yes it can be done... method we've already explained in theory videos...

[@srihariks6693]

sir how can we conserve angular momentum as there is an external force produced by cue ....???

[@smittavate5790]

how???

[@sonamkaurkhurana290]

Sir how can you take moment of inertia to be 2/3MR^2

[@tanishkorgaonkar944]

Shell implies hollow sphere

[@arvindgupta4129]

On 1:41 u have not mentioned "h" on right side

[@physicsgalaxyworld]

On right hand side we have used angular momentum as product of MI and angular speed so h will not be there on RHS... watch carefully...

[@srihariks6693]

why is force of friction zero in this case ...????

[@adarshchaturvedi3498]

as there is no ext force , its just a sudden blow

[@surya8891]

how to solve the problem given below ...i tried to use energy conservation , but i don't get the asnwer .

[@physicsgalaxyworld]

replied below... but queries other than above video you should not ask as this may distract other viewers... you can post these queries on INTERACT tab of our website www.physicsgalaxy.com

[@surya8891]

ohh ...

[@rajeevkumarsam5499]

Sir in this question why not you taking friction.

[@tanishkorgaonkar944]

No external force is applied

[@puneethgowda6819]

Sir I have a small confusion when do we have to use work energy theorem and energy conservation in rotational motion

[@physicsgalaxyworld]

work energy theorem is preferred... however energy conservation is equally fine...

[@rahulprasad8243]

Sir what about impulse due to friction?

[@mehbubahmed7973]

Rahul Prasad there will no friction because of no slipping

[@annuyadav2307]

Is it sufficient for jee advance