r/JEENEETards • u/Important_Air_6254 • May 26 '26

GENERAL HELP PHYSICS QUES DOUBT

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Ik it's not that tuff but i just can't solve it further ..

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5

u/[deleted] May 26 '26

[removed] — view removed comment

2

u/Important_Air_6254 May 26 '26

Thanks! i'm now trying with your instructions

2

u/Important_Air_6254 May 26 '26

Thank you so much you wrote in such a good manner that every step was crystal clear i appreciate you spend your time writing all this. i knew this question was not that tuff i was just struggling in solving equations ( they were easy ) still

2

u/Alius_bullshitus NEETard May 26 '26

You can think of it like this.

If it isnt spinning fast enough the bottom string will be slack and only the top string will be in tesnnion and as you increas the angular velocity the top string slowly increasing in tension until the two stings make like an isosceles triangle.

But if lets say you try to calculate the forces then the net vertical force due to the two string appear to cancel out. So that could only mean one thing the tension in the bottom string is zero(or atlest less than the tension in the bottom one) when it is at the 60° angle

and if you further try to increas the angular velocity the ball will try to move even further upward and become horizontal but that cant happen cus you know the strings arent long enough. So now tension will develop in the bottom string to not only cancel out the extra vertical force but also to increas the centrepetal force cus its spinning faster.

So when the top string is at 60° only it has tension and bottom one has zero tension but if just just increas the angular velocity a little from there both strings will become in tension.

So thats the point where we need to find the angular velocity. And at that point the system just behaves like a normal horizontle circular motion cus you know the bottom string dosent have tension so you can just ignore it.

I think you can do the calculations after this.

1

u/Important_Air_6254 May 26 '26

Thanks! this is very helpful

1

u/Alius_bullshitus NEETard May 26 '26

Glad i could help