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# moment watch

1. For Question B I got 3 unknown and when I sub in the equation. always get 0
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2. (Original post by Mars Chan)
For Question B I got 3 unknown and when I sub in the equation. always get 0
I cannot see reactions in your diagram but the reaction at C will be zero
3. (Original post by TeeEm)
I cannot see reactions in your diagram but the reaction at C will be zero
yep C is R1 and I already find out the equation of moment of C
4. (Original post by Mars Chan)
yep C is R1 and I already find out the equation of moment of C
when the mass is max, the reaction at C is zero
5. (Original post by TeeEm)
when the mass is max, the reaction at C is zero
My friend told me that as well. But can you explain me why?
6. (Original post by Mars Chan)
My friend told me that as well. But can you explain me why?
I wish I could but my brain is severely constipated after teaching non stop from 13.00 to 23.00.
Ask me the same question tomorrow and I promise not to evade you

7. (Original post by TeeEm)
I wish I could but my brain is severely constipated after teaching non stop from 13.00 to 23.00.
Ask me the same question tomorrow and I promise not to evade you

is ok thank you for answering.
8. (Original post by Mars Chan)
is ok thank you for answering.
Resolve vertically. You now have a constraint. on T_c.
9. (Original post by TeeEm)
I wish I could but my brain is severely constipated after teaching non stop from 13.00 to 23.00.
Ask me the same question tomorrow and I promise not to evade you

Hello if you have time can you answer me thank you
10. (Original post by Mars Chan)
Hello if you have time can you answer me thank you
If you increase the mass at B, bit by bit there will come an instant where the rod will topple over (equilibrium is broken by turning about D)

When this happens the rod will not be touching the support at C in other words the reaction at C will be zero
11. (Original post by TeeEm)
If you increase the mass at B, bit by bit there will come an instant where the rod will topple over (equilibrium is broken by turning about D)

When this happens the rod will not be touching the support at C in other words the reaction at C will be zero
sorry what do you mean by equilibrium is broken by turning about D
12. (Original post by Mars Chan)
sorry what do you mean by equilibrium is broken by turning about D
can't you visualize that?

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