Equilibrium of three suspended blocksby Phys121VIU Tags: blocks at rest, coplanar forces, equilibrium, three blocks 

#1
Jan2012, 12:23 PM

P: 17

1. The problem statement, all variables and given/known data
http://imageshack.us/photo/myimages/851/45009287.png/ The problem(s) are shown in the link, but I'm having trouble getting them started. 2. Relevant equations 3. The attempt at a solution For 312: I think what I need to do is find the tension force in the ropes leading from each block to point A. Then with those forces I find the Sum of the forces in X and Y From there i think i know what to do, its just that i dont know how to find the force in each rope! My attempt: For block B, the force in the the rope to point A is sin∅/200lb. For block C, the force in the rope to point a is sin(30)/100 =50lb . Is this correct so far? 



#2
Jan2012, 12:35 PM

Mentor
P: 40,905

Careful how you write things: don't confuse sin(30)/100 with 100*sin(30). 



#3
Jan2012, 04:02 PM

P: 17

The tension in the ropes are equal to the weight of the blocks, so rope AB is 200lb and AC is 100lb. Then I find the Sum of forces for X and Y and solve for the unknowns! Thanks! 


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