Part A

Learning Goal:

To analyze the forces within space truss members and the reaction

forces that act on space trusses.

A space truss is a stable three$-$dimensional structure that consists of

members joined at their ends. If the external loading is applied at the

joints, and the joints are ball$-$and$-$socket connections, the members of

a space truss may be treated as two$-$force members.

Figure

$1$ of $2$

A space truss is subjected to a load of $F=\{100i-480k\}lb($Figure $1)$ Three ball$-$and$-$socket joints at $C,E,$ and $G$ support the space truss. If $F_x=100lb,F_z=$

$480lb$ in the negative $z$ direction, and $d=5\mathrm{.}00ft,$ what is the magnitude of the force in member $AC?$ Indicate a tensile force as a positive value and a compressive

force as a negative value.

Express your answer numerically to three significant figures in pounds.

View Available Hint$($s$)$

$F_{AC}=$

$lb$

Part B

As shown, a space truss is the frame for a building's awning. $($Figure $2)$ Three ball$-$and$-$socket joints at $A,B,$ and $E$ support the frame. If a force of

$F=\{160i+360j\}N$ is applied at point $D,$ what are the forces in each member? Indicate a tensile force as a positive value and a compressive force as a negative

value.

Express your answers numerically to three significant figures in newtons separated by commas.

View Available Hint$($s$)$

$F_{DA},F_{DC},F_{DB},F_{CA},F_{CB},F_{CE}=$