Question

I need help with the following problem: Determine the tensions in wires cd, cb, and ba and the angle theta required for equilibrium of the 90lb cylinder E and the 30lb cylinder F

Answer 1

Sorry for the delay, this group isn't very active.

First, let's start by drawing a FBD about the links at C and B. You should realize the following equations.

FBD of link C:\[\sum F_y = 0 \rightarrow -m_E g + T_{CD} \sin(30) - T_{CB} \sin(\theta) = 0\]\[\sum F_x = 0 \rightarrow -T_{CD} \cos(30) + T_{CB} \cos(\theta) = 0\]
FBD of link B:\[\sum F_y = 0 \rightarrow -m_F g + T_{CB} \sin(\theta) + T_{BA} \sin(45) = 0\]\[\sum F_x = 0 \rightarrow -T_{CB} \cos(\theta) + T_{BA} \cos(45) = 0\]

We have four equations and four unknowns.