Problem $3$: Method of Sections

Inputs:

$h=12ft$

$b=7ft$

$F_1=2100lb$

$F_2=800lb$

$=25$

You must use the method of sections as described below.

You will not receive credit if you use the method of joints!

Take a horizontal section cut through the middle of the truss and keep the top portion for your FBD$.$ That way you don't have to bother with the reactions at A and D$.$

Using the FBD of the top portion of the truss, perform the following steps:

a$)$ Use $F_x=0$ to compute BD$.$ Indicate tension vs$.$ compression.

b$)$ Use $M_D=0$ to compute $AB.$ Indicate tension vs$.$ compression.

c$)$ Use $M_B=0$ to compute $CD.$ Indicate tension vs$.$ compression.

d$)$ Use $F_y=0$ to check all values