Anyone?
The strings are light and inelastic, and the pulleys are light and smooth. Find, the acceleration of A and the tension in the strings.
-Attached.

Question

Anyone? 
The strings are light and inelastic, and the pulleys are light and smooth. Find, the acceleration of A and the tension in the strings. 
-Attached.

anonymous · Answer

attachment

anonymous · Answer

did you draw the free-body diagram?

anonymous · Answer

Yes.

anonymous · Answer

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anonymous · Answer

the trick is, how are the three accelerations related?

anonymous · Answer

it is one long string...
distance the first one moves in time "t"
$$d_1={1\over2}a_1t^2$$
in the same time, second one moves:
$$d_2={1\over2}a_2t^2$$
in this time, the object A moves:$d_1+d_2$ so, its acceleration would be:
$$a_1+a_2=a_A$$

anonymous · Answer

you'd now have three simultaneous linear equations

anonymous · Answer

$$T_1=2a_1\
T_2=3a_2\
4g-T_1-T_2=4a_A$$

anonymous · Answer

no wait..
the distance that the 4kg mass moves down is the "AVERAGE" of d1 and d2

anonymous · Answer

An why is that? :O

anonymous · Answer

*And

anonymous · Answer

coz, otherwise, the 4kg mass would shift and hang in the AIR!!!

anonymous · Answer

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