# Mechanics Problem HELP!

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Thread starter 3 years ago
#1
Sorry to bug everyone, but really stuck on this question, any hints greatly appreciated!
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Thread starter 3 years ago
#2
(Original post by marinacalder)
Sorry to bug everyone, but really stuck on this question, any hints greatly appreciated!
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reply
3 years ago
#3
(Original post by marinacalder)
...
General points:

1) Try and get all your information into the first post - if there's more than one post it gives the impression, on a quick glance, that the thread has been replied to.

2) Upright photos would be appreciated.

Regarding your actual question.

What can you tell me about the relationship between the forces in the two strings, using the information that's been given?

Now resolve vertically.

Now take moments about A.
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3 years ago
#4
(Original post by marinacalder)
You have upward tensions at A and B, but it's twice as big at A since ext is double there.

At centre of grav, moments balance. In each case you're angle @ (to horiz) from making a right angle between rod and force, for purposes of taking moments.

L_a = distance of centre of grav from A, L_b = L - L_a:
[email protected]_a = (T/2)[email protected](L - L_a)
=> 2.L_a = L - L_a
=> L_a = L/3

Centre of grav is 1/3 of rod's length from A.
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