AlishaWhite
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RDKGames
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(Original post by AlishaWhite)
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What have you tried?
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(Original post by RDKGames)
What have you tried?
normally you would equate potential energy to kinetic but it wants the end of the rod and it is a rotation. So it wouldnt be mgh = 0.5mv²
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(Original post by AlishaWhite)
normally you would equate potential energy to kinetic but it wants the end of the rod and it is a rotation. So it wouldnt be mgh = 0.5mv²
Yep, so you need to consider rotational K.E.

How much GPE does the rod lose in the process of motion?

This must be equal to the rotational KE when the rod is vertical, and this is given by \dfrac{1}{2}I\omega^2, where I is the moment of intertia of the rod about the end which is fixed to the ceiling, and \omega is the angular speed.

Rearrange this equality for \omega. Then clearly, velocity of the other end of the rod is v = l\omega
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(Original post by RDKGames)
Yep, so you need to consider rotational K.E.

How much GPE does the rod lose in the process of motion?

This must be equal to the rotational KE when the rod is vertical, and this is given by \dfrac{1}{2}I\omega^2, where I is the moment of intertia of the rod about the end which is fixed to the ceiling, and \omega is the angular speed.

Rearrange this equality for \omega. Then clearly, velocity of the other end of the rod is v = l\omega
In E = mgh

would h = L or would it be 0.5L
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(Original post by AlishaWhite)
In E = mgh

would h = L or would it be 0.5L
It's a uniform rod, so the CoM is halfway along the rod.
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AlishaWhite
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(Original post by RDKGames)
It's a uniform rod, so the CoM is halfway along the rod.
Ok thanks.

Not rlly sure on this on either:
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Ok thanks.

Not rlly sure on this on either:
1/total resistance for the LHS would be (1/R1+R2)+1/R3 and so you equate that to Rtot of the RHS which is (1/Rp+2R3), make Rp the subject
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(Original post by Varss)
1/total resistance for the LHS would be (1/R1+R2)+1/R3 and so you equate that to Rtot of the RHS which is (1/Rp+2R3), make Rp the subject
I got the LHS but for RHS did u mean 1/(Rp + 2R3) or (1/Rp) + 2R3
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(Original post by AlishaWhite)
I got the LHS but for RHS did u mean 1/(Rp + 2R3) or (1/Rp) + 2R3
sorry that's my fault lol I meant 1/(Rp)+2/(R3)
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