# how to do b

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#1
what is wrong here with b
0
7 months ago
#2
(Original post by Hedwigeeeee)
what is wrong here with b
The mass at B has been removed, so there is no "4x50g" when taking moments about A.
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#3
(Original post by ghostwalker)
The mass at B has been removed, so there is no "4x50g" when taking moments about A.
but the answer is still different... can u get the correct value?
0
7 months ago
#4
(Original post by Hedwigeeeee)
but the answer is still different... can u get the correct value?
Should also note that Rp+Rq = 20g, not 70g.

Does that sort it - if not post working.
1
7 months ago
#5
Now that the mass at B has been removed, the reaction forces at P & Q will total 20g. You know the distance of the centre of mass from A, which means you can work out how far away it is from P or Q. Take moments about P or Q to give you the reaction force at that point, then subtract this from 20g to find the other reaction force.

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Moments about P: 1.75x20g = 3xRQ
Therefore, RQ=(35/3)g
20g - (35/5)g = (25/3)g = RP
Last edited by mathstutor24; 7 months ago
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