(adsbygoogle = window.adsbygoogle || []).push({}); Please help Due in 2 hours. Statics machine equilibrium: reactions- too many unknowns

1. The problem statement, all variables and given/known data

The woman using the lat pulldown machine is holding the 80-lb weight stationary in the position shown. What are the reactions at the built-in support E and pin support F? (A and C are pinned connections)

3. The attempt at a solution

First, I isolated the pulleys and rope to find the components of the tension at D.

D_{x}=80cos60=40 lb

D_{y}=-40√3 lb

Then I set up my three equilibrium equations:

∑M_{E}=0= -(80 lb)(13/6 ft) - (40√3 lb)(17/3 ft) - (40 lb)(27/4 ft) + M_{E}+ F_{y}(25/6 ft)

M_{E}= (680√3)/3 +1330/3 + (25/6)F_{y}

∑F_{x}= 0 = E_{x}+ F_{x}+ (40 lb)

∑F_{y}= 0 = E_{y}+ F_{y}- (80 lb) - (40√3 lb)

Right now, I have 3 equations and 5 unknowns, E_{x}, E_{y}, M_{E}, F_{x}, and F_{y}.

I'm probably supposed to break it up into two systems, first just the top portion. But I'm not really sure how to proceed from here.

Thank you!

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# Homework Help: Statics machine equilibrium: support reaction- I have too many unknowns

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