Tensions and Constraints

1. Oct 21, 2009

makeez

Hi All

1. The problem statement, all variables and given/known data
http://img101.photolava.com/2009/10/...r-vswpt7nk.jpg [Broken]
Ac is given to be 20mms-2 and Ab=0mms-2.
The masses of A C D are 10kg

2. Relevant equations

3. The attempt at a solution
I found the following constraints by differentiating distance constraints of the rope.
2Aa + 2Ab + Ac = 0
2Ad - Aa - Ab = 0
I solved these simultaneously to get the acclerations
Aa=-10mms-2 Ad=-5mms-2, while
Is this corrent and if so how do I go about solving question c?
I tried summing the forces around blocks but my answers where inconsistant depending on which block I used, for example on block c ma=Tension of rope ABC - mg
or on block a ma = 2*tension of rope ABC - tension of rope ABD - mg
or on block d ma = 2*tension of rope ABD - mg.
what am I doing wrong?
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

Last edited by a moderator: May 4, 2017
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