Congratulations for being selected to represent India in ijso.
Also what about JOMPC?
–
Shivam Jadhav
·
1 year, 1 month ago

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@Shivam Jadhav
–
rajdeep bhaiya online hai aur onhone ntse ke liye apply kiya tha
–
Real Champ
·
2 weeks, 5 days ago

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@Shivam Jadhav
–
Thanks. It will be out day after tomorrow. I have marked all the solutions I'll compile and post it on monday.
–
Rajdeep Dhingra
·
1 year, 1 month ago

nishant,ayushman,gaurang inme se kisine ntse clear kiya or aap school ke exams ke samay sirf school ka padte hai ya coaching ka bhi padte hai.
–
Real Champ
·
2 weeks, 3 days ago

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bhaiya mai ijso or ipho ke liye prepare kar raha ho toh mai kaise school ke saath use bhi padho or aapke 10 me kitne number thay
–
Real Champ
·
2 weeks, 3 days ago

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bhaiya yeh bata dijye ki school me jo course hai(icse) ka since i am in class 10 then how i can maintain a fine balance between academics and competitive study .
–
Real Champ
·
2 weeks, 3 days ago

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you are an ijso gold medalist or app to school ke bad coaching allen bhi jaate hai toh fir aap apna time kaise balance karte hai
–
Real Champ
·
2 weeks, 3 days ago

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BHAIYA IJSO KE LIYE KAUN SI BOOK SE PADHE AUR ASTRONOMY KE LIYE KISE PADHE
–
Real Champ
·
2 weeks, 5 days ago

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bhaiya pls reply
–
Real Champ
·
2 weeks, 6 days ago

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bhaiya physics olympiad ke liye kis book se theory padhe aur aapne ne ntse ke liye apply kiya tha
–
Real Champ
·
2 weeks, 6 days ago

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rajdeep u r of which coaching allen or fiitjee
–
Real Champ
·
1 month ago

@Rajdeep Dhingra
–
you are an ijso gold medalist or app to school ke bad coaching allen bhi jaate hai toh fir aap apna time kaise balance karte hai or aap ne allen kis class mai join kiya tha
–
Real Champ
·
2 weeks, 3 days ago

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@Rajdeep Dhingra
–
pls help me bhaiya mai koi bhi nse ke paper ke liye kaise apply karo jab mera school register na ho toh since u r an ijso gold medalist u must have an idea about this question aur kya mai class 10 mai nsejs me apply kar sakta ho aapne kis class mai apply nsejs ke liye apply kiya tha.if u have any books then suggest me books for ijso and ipho
–
Real Champ
·
2 weeks, 6 days ago

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@Real Champ
–
I applied for NSEJS in class 9th. If your school isn't Registered , go to the nearest KV School and asked them to register you. For NSEJS simply do NCERT 9,10,11.(P,C,B). For maths practice past year papers or extra questions from NTSE type books.
–
Rajdeep Dhingra
·
2 weeks, 6 days ago

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@Rajdeep Dhingra
–
bhaiya mai ijso or ipho ke liye prepare kar raha ho toh mai kaise school ke saath use bhi padho or aapke 10 me kitne number thay
–
Real Champ
·
2 weeks, 3 days ago

Log in to reply

@Rajdeep Dhingra
–
nishant,ayushman,gaurang inme se kisine ntse clear kiya or aap school ke exams ke samay sirf school ka padte hai ya coaching ka bhi padte hai.
–
Real Champ
·
2 weeks, 3 days ago

Log in to reply

@Rajdeep Dhingra
–
i would like to share a simple problem with which u might have suffer.problem is that while preparing for ipho and ijso i am unable to study for boards and whenever i take leave from my school then i used to have scolds from principal of school .what is the average time an student should devote for preparing ipho and for application process in any foreign university like pennsylvania,california,mit.how u made a balance between ur school studies and competitive studies.u appeared for ntse or not.
–
Real Champ
·
2 weeks, 6 days ago

@Real Champ
–
i would like to share a simple problem with which u might have suffer.problem is that while preparing for ipho and ijso i am unable to study for boards and whenever i take leave from my school then i used to have scolds from principal of school .what is the average time an student should devote for preparing ipho and for application process in any foreign university like pennsylvania,california,mit.how u made a balance between ur school studies and competitive studies.u appeared for ntse or not.
–
Real Champ
·
2 weeks, 6 days ago

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@Real Champ
–
I did appear for NTSE , but couldn't make it to the next round as my SST is poor.
–
Rajdeep Dhingra
·
2 weeks, 5 days ago

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@Rajdeep Dhingra
–
similar will be the case with mine since my sst is poor and how to manage time or make a balance between academics and studies for ipho and ijso
–
Real Champ
·
2 weeks, 4 days ago

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@Rajdeep Dhingra
–
BHAIYA AAP KI ENGLISH TO KAAFI ACHI AUR ACCURATE HAI AAP TOEFL KE LIYE PRACTICE KAR RAHE HAI KYA
–
Real Champ
·
2 weeks, 4 days ago

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@Rajdeep Dhingra
–
BHAIYA CORSERA.ORG IS A VERY GOOD WEBSITE BUT HOW TO LEARN FROM IT
–
Real Champ
·
2 weeks, 4 days ago

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@Rajdeep Dhingra
–
BHAIYA AAPNE IJSO AUR IPHO ALONG WITH BOARDS KE LIYE KAISE TIME MANAGEMENT KIYA
–
Real Champ
·
2 weeks, 4 days ago

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@Real Champ
–
can u share ur phone number with me as or any mailid on google or yahoo as i ahve a lot of queries regarding nse's exams and how u study from coursera.org
–
Real Champ
·
2 weeks, 6 days ago

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Which book is it?
–
Ritik Gandhi
·
5 months, 2 weeks ago

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@Ritik Gandhi
–
I answered it before also , an old JEE subjective book. Just Mechanics for JEE is written on the book , nothing else.
–
Rajdeep Dhingra
·
5 months, 2 weeks ago

@Rajdeep Dhingra
–
And what about the above book(the one from which you sent questions?
Any clue through which I might be able to access the book?
–
Rasty Rocky Yoyo
·
2 months ago

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@Rasty Rocky Yoyo
–
I think new Editions of it has been published by balaji publications. JEE Mechanics or something like that.
–
Rajdeep Dhingra
·
2 months ago

Bro is your second doubt cleared ? i am getting it's answer as root 5g/7(R-r) tell if not cleared i will give the solution ( if my answer is correct.) .
–
Brilliant Member
·
11 months ago

Hy rajdeep, can u give some tips for prepartion of nsejs , as my brother will be giving this year, presently he is in class 9.
–
Rahul Bubna
·
1 year, 1 month ago

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@Rahul Bubna
–
Read 9th and 10th class NCERT books thoroughly , if possible read 11th and 12th class NCERT also.(only relevant topics). For NSEJS most important is your speed of solving questions.
–
Rajdeep Dhingra
·
1 year, 1 month ago

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@Rajdeep Dhingra
–
If he starts from June 10 , is he will be able to clear nsejs ? He also goes to coaching ...
–
Rahul Bubna
·
1 year, 1 month ago

Question 2:
Let \( f \)denote the friction force acting on the body. Now, ablut the center of mass writing the torque equation,
\( f \cdot r = \dfrac{MR^{2}\alpha}{2} \)
\( f = \dfrac{MR\alpha}{2} \)
But since the cylinder doesn't slip \( r \alpha = a_{cm} \)
\( f = \dfrac{ma_{cm}}{2} \)
Now,
\( mg\sin(\theta) - f = ma_{cm} \)
\( mg\sin(\theta) = \dfrac{3ma_{cm}}{2} \)
\( a_{cm} = \dfrac{2g\sin(\theta)}{3} \)
\( \alpha = \dfrac{2g \sin(\theta)}{3r} \)
For small values of \( \theta \), \( \sin(\theta) \approx \theta \)
\( \alpha = - \dfrac{2g \theta}{3r} \)
The negative sign just denotes that direction of alpha is opposite to displacement.
This is the rotational analogue of \( a = -\omega^{2}x \)
\( \therefore \omega = \sqrt{\dfrac{2g}{3r}} \)
Frequency \( \dfrac{\omega}{2\pi} = \dfrac{1}{2\pi} \sqrt{\dfrac{2g}{3r}} \)
–
Vighnesh Shenoy
·
1 year, 1 month ago

Log in to reply

@Vighnesh Shenoy
–
It is wrong bro. \( \theta\) is the angle you moved the center of mass not the angle by which you rotated the sphere. Hence you can't equate \( {\omega}^2 \) to \(\dfrac{2g}{3r}\).
–
Rajdeep Dhingra
·
1 year ago

## Comments

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TopNewestCongratulations for being selected to represent India in ijso. Also what about JOMPC? – Shivam Jadhav · 1 year, 1 month ago

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– Real Champ · 2 weeks, 5 days ago

rajdeep bhaiya online hai aur onhone ntse ke liye apply kiya thaLog in to reply

– Rajdeep Dhingra · 1 year, 1 month ago

Thanks. It will be out day after tomorrow. I have marked all the solutions I'll compile and post it on monday.Log in to reply

– Ritik Gandhi · 3 months, 1 week ago

?????Log in to reply

– Rajdeep Dhingra · 3 months, 1 week ago

JOMC was a contest , I had to take out the result.Log in to reply

– Real Champ · 2 weeks ago

bhaiya aapne brilliant premium lifetime ke liye kitna pay kiya thaLog in to reply

nishant,ayushman,gaurang inme se kisine ntse clear kiya or aap school ke exams ke samay sirf school ka padte hai ya coaching ka bhi padte hai. – Real Champ · 2 weeks, 3 days ago

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bhaiya mai ijso or ipho ke liye prepare kar raha ho toh mai kaise school ke saath use bhi padho or aapke 10 me kitne number thay – Real Champ · 2 weeks, 3 days ago

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bhaiya yeh bata dijye ki school me jo course hai(icse) ka since i am in class 10 then how i can maintain a fine balance between academics and competitive study . – Real Champ · 2 weeks, 3 days ago

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you are an ijso gold medalist or app to school ke bad coaching allen bhi jaate hai toh fir aap apna time kaise balance karte hai – Real Champ · 2 weeks, 3 days ago

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BHAIYA IJSO KE LIYE KAUN SI BOOK SE PADHE AUR ASTRONOMY KE LIYE KISE PADHE – Real Champ · 2 weeks, 5 days ago

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bhaiya pls reply – Real Champ · 2 weeks, 6 days ago

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bhaiya physics olympiad ke liye kis book se theory padhe aur aapne ne ntse ke liye apply kiya tha – Real Champ · 2 weeks, 6 days ago

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rajdeep u r of which coaching allen or fiitjee – Real Champ · 1 month ago

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– Rajdeep Dhingra · 3 weeks, 5 days ago

I was first in fiitjee , now in allen.Log in to reply

– Real Champ · 2 weeks, 3 days ago

you are an ijso gold medalist or app to school ke bad coaching allen bhi jaate hai toh fir aap apna time kaise balance karte hai or aap ne allen kis class mai join kiya thaLog in to reply

– Real Champ · 2 weeks, 6 days ago

pls help me bhaiya mai koi bhi nse ke paper ke liye kaise apply karo jab mera school register na ho toh since u r an ijso gold medalist u must have an idea about this question aur kya mai class 10 mai nsejs me apply kar sakta ho aapne kis class mai apply nsejs ke liye apply kiya tha.if u have any books then suggest me books for ijso and iphoLog in to reply

– Rajdeep Dhingra · 2 weeks, 6 days ago

I applied for NSEJS in class 9th. If your school isn't Registered , go to the nearest KV School and asked them to register you. For NSEJS simply do NCERT 9,10,11.(P,C,B). For maths practice past year papers or extra questions from NTSE type books.Log in to reply

– Real Champ · 2 weeks, 3 days ago

bhaiya mai ijso or ipho ke liye prepare kar raha ho toh mai kaise school ke saath use bhi padho or aapke 10 me kitne number thayLog in to reply

– Real Champ · 2 weeks, 3 days ago

nishant,ayushman,gaurang inme se kisine ntse clear kiya or aap school ke exams ke samay sirf school ka padte hai ya coaching ka bhi padte hai.Log in to reply

– Real Champ · 2 weeks, 6 days ago

i would like to share a simple problem with which u might have suffer.problem is that while preparing for ipho and ijso i am unable to study for boards and whenever i take leave from my school then i used to have scolds from principal of school .what is the average time an student should devote for preparing ipho and for application process in any foreign university like pennsylvania,california,mit.how u made a balance between ur school studies and competitive studies.u appeared for ntse or not.Log in to reply

– Real Champ · 2 weeks, 6 days ago

pls replyLog in to reply

– Real Champ · 2 weeks, 6 days ago

bhaiya aapne brilliant.org pe register ke liye kitne rupaye pay kiyeLog in to reply

– Real Champ · 2 weeks, 6 days ago

bhaiya can u suggest me books for ijsoLog in to reply

– Real Champ · 2 weeks, 6 days ago

i would like to share a simple problem with which u might have suffer.problem is that while preparing for ipho and ijso i am unable to study for boards and whenever i take leave from my school then i used to have scolds from principal of school .what is the average time an student should devote for preparing ipho and for application process in any foreign university like pennsylvania,california,mit.how u made a balance between ur school studies and competitive studies.u appeared for ntse or not.Log in to reply

– Rajdeep Dhingra · 2 weeks, 5 days ago

I did appear for NTSE , but couldn't make it to the next round as my SST is poor.Log in to reply

– Real Champ · 2 weeks, 4 days ago

similar will be the case with mine since my sst is poor and how to manage time or make a balance between academics and studies for ipho and ijsoLog in to reply

– Real Champ · 2 weeks, 4 days ago

BHAIYA AAP KI ENGLISH TO KAAFI ACHI AUR ACCURATE HAI AAP TOEFL KE LIYE PRACTICE KAR RAHE HAI KYALog in to reply

– Real Champ · 2 weeks, 4 days ago

BHAIYA CORSERA.ORG IS A VERY GOOD WEBSITE BUT HOW TO LEARN FROM ITLog in to reply

– Real Champ · 2 weeks, 4 days ago

BHAIYA AAPNE IJSO AUR IPHO ALONG WITH BOARDS KE LIYE KAISE TIME MANAGEMENT KIYALog in to reply

– Real Champ · 2 weeks, 6 days ago

can u share ur phone number with me as or any mailid on google or yahoo as i ahve a lot of queries regarding nse's exams and how u study from coursera.orgLog in to reply

Which book is it? – Ritik Gandhi · 5 months, 2 weeks ago

Log in to reply

– Rajdeep Dhingra · 5 months, 2 weeks ago

I answered it before also , an old JEE subjective book. Just Mechanics for JEE is written on the book , nothing else.Log in to reply

– Rasty Rocky Yoyo · 2 months, 1 week ago

hi rajdeep bhaiya which all books do u refer for physics olympiad?Log in to reply

– Rajdeep Dhingra · 2 months ago

Irodov , Past Papers , Arvind Tiwari's Book for practice and Cengage for theory.Log in to reply

– Rasty Rocky Yoyo · 2 months ago

how is krotov?Log in to reply

– Rajdeep Dhingra · 2 months ago

It is good , like irodov only , but I haven't done it much.Log in to reply

– Rasty Rocky Yoyo · 2 months ago

And what about the above book(the one from which you sent questions? Any clue through which I might be able to access the book?Log in to reply

– Rajdeep Dhingra · 2 months ago

I think new Editions of it has been published by balaji publications. JEE Mechanics or something like that.Log in to reply

– Rasty Rocky Yoyo · 2 months ago

Can you please reply?Log in to reply

– Ritik Gandhi · 3 months, 1 week ago

who's the author of the book?Log in to reply

– Rajdeep Dhingra · 3 months, 1 week ago

I don't know.Log in to reply

– Ritik Gandhi · 3 months, 1 week ago

publication?Log in to reply

– Rajdeep Dhingra · 3 months, 1 week ago

BalajiLog in to reply

– Ritik Gandhi · 3 months, 1 week ago

Ok thank you! Can you please send a pic of the cover page?Log in to reply

– Rajdeep Dhingra · 3 months, 1 week ago

I don't have the cover page , It is torn. Even the 1st Chapter is missing.Log in to reply

– Ritik Gandhi · 5 months, 1 week ago

who's the author of the book?Log in to reply

– Ritik Gandhi · 4 months, 3 weeks ago

??Log in to reply

Bro is your second doubt cleared ? i am getting it's answer as root 5g/7(R-r) tell if not cleared i will give the solution ( if my answer is correct.) . – Brilliant Member · 11 months ago

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– Rajdeep Dhingra · 11 months ago

Cleared. Thanks anyways. P.S : your answer is correct.Log in to reply

Hey @Rajdeep Dhingra why not coming to fiitjee ? PLease tell the truth !! – Parth Bhardwaj · 11 months, 2 weeks ago

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– Real Champ · 1 month ago

rajdeep u are of which coaching allen or fiitjeeLog in to reply

Which book is it ? – John Verghese · 1 year, 1 month ago

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– Rajdeep Dhingra · 1 year, 1 month ago

I don't know. Some old book for JEE subjective.Log in to reply

Hy rajdeep, can u give some tips for prepartion of nsejs , as my brother will be giving this year, presently he is in class 9. – Rahul Bubna · 1 year, 1 month ago

Log in to reply

– Rajdeep Dhingra · 1 year, 1 month ago

Read 9th and 10th class NCERT books thoroughly , if possible read 11th and 12th class NCERT also.(only relevant topics). For NSEJS most important is your speed of solving questions.Log in to reply

– Rahul Bubna · 1 year, 1 month ago

If he starts from June 10 , is he will be able to clear nsejs ? He also goes to coaching ...Log in to reply

– Rajdeep Dhingra · 1 year, 1 month ago

I think so.Log in to reply

Question 2:

Let \( f \)denote the friction force acting on the body. Now, ablut the center of mass writing the torque equation,

\( f \cdot r = \dfrac{MR^{2}\alpha}{2} \)

\( f = \dfrac{MR\alpha}{2} \)

But since the cylinder doesn't slip \( r \alpha = a_{cm} \)

\( f = \dfrac{ma_{cm}}{2} \) Now,

\( mg\sin(\theta) - f = ma_{cm} \)

\( mg\sin(\theta) = \dfrac{3ma_{cm}}{2} \)

\( a_{cm} = \dfrac{2g\sin(\theta)}{3} \)

\( \alpha = \dfrac{2g \sin(\theta)}{3r} \)

For small values of \( \theta \), \( \sin(\theta) \approx \theta \)

\( \alpha = - \dfrac{2g \theta}{3r} \)

The negative sign just denotes that direction of alpha is opposite to displacement.

This is the rotational analogue of \( a = -\omega^{2}x \)

\( \therefore \omega = \sqrt{\dfrac{2g}{3r}} \)

Frequency \( \dfrac{\omega}{2\pi} = \dfrac{1}{2\pi} \sqrt{\dfrac{2g}{3r}} \) – Vighnesh Shenoy · 1 year, 1 month ago

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– Rajdeep Dhingra · 1 year ago

It is wrong bro. \( \theta\) is the angle you moved the center of mass not the angle by which you rotated the sphere. Hence you can't equate \( {\omega}^2 \) to \(\dfrac{2g}{3r}\).Log in to reply

– Brilliant Member · 8 months ago

it would be 5g/7r instead !Log in to reply

– Rajdeep Dhingra · 1 year, 1 month ago

ThanksLog in to reply

@aryan goyat@Prakhar Bindal@Archit Agrawal@Aniket Sanghi Please help – Rajdeep Dhingra · 1 year, 1 month ago

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Solution for Question 1:Log in to reply

– Rajdeep Dhingra · 1 year, 1 month ago

Thanks !Log in to reply

– Saarthak Marathe · 1 year, 1 month ago

You are welcomeLog in to reply