See Picture, The problem gives three boxes(M1, M2, and M3) and a few pulleys, no value for the coefficient of friction is given. None of the masses are known, and we are told to assume M1 and M3 are sliding. The objective is to find Ft
The Attempt at a Solution
First I started of by drawing free body diagrams for all of the boxes, Using these(and assuming M1 and M2 are sliding towards the middle) I came up with
M2 Would then have the same equations except M1 would be M2 because it also has
(I feel like that might be wrong but I'm not sure)
I'm not sure about the signs on all of those either.
Then I have for M3
At this point I'm not sure what to do, (the lack of values is killing me) I would think putting Ft from the M1 equation into the Ft equation would be a good start, but then everything except mass would cancel wouldn't it? So that doesn't seem right. I feel like I'm going in the right direction and I need to use these equations simultaneously some how but I'm not sure what to do for the next step as I don't see how this is going to get me Ft.
Also I'm starting to think M2 Net force is different
FNET=Ff-Ft (Since the ropes would be moving in opposite directions) and that would also change the equation for M2 to
But even if that's right, what would i do with it...?
Any help is appreciated, I'm currently stumped.