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may I know whether the tension on the two strings are the same, the picture is attached. enter image description here

Thank you very much for your reply.

Henry Cai
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  • If there is gravity, the answer would have to be "No", because the A string is taking all the force of gravity in the left-hand picture, but shares it with the B string in the right-hand picture. – Adrian Keister Jan 03 '20 at 16:17
  • Physicsstackexchange is the next door. EDIT: Just saw calssical mechanics tag, so physicists made their way in here. OMG – tommy1996q Jan 03 '20 at 16:17
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    If there is no gravity, you still expect the tensions to be different because there is no vertical acceleration, so the vertical components of the tension must cancel out. – almagest Jan 03 '20 at 16:19

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Suppose the tension in the upper string is $T_1$ and in the lower string $T_2$. Let the radius be $r$, the speed $v$ and the mass $m$.

Resolving vertically we get $T_1\cos\theta=T_2\cos\phi+mg$ (assuming there is gravity - leave out the $mg$ if not). Resolving horizontally we get $T_1\sin\theta+T_2\sin\phi=mv^2/r$.

So in general we do not expect $T_1=T_2$.

almagest
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