Engineering Statics

D-13


Using method of joints, determine the force in each member of the truss shown. State whether each member is in tension or compression.


A FBD of the truss is drawn.
A moment equation is taken about point A to find B<sub>x</sub>.
A moment equation is taken about point B to find A<sub>x</sub>.
The force equation in the y direction gives a relationship between the 
two vertical external force.  Note how two moment equations and only one 
force equation have been used.  Any three independent equations may be 
used.
The forces at A have been drawn.


The forces at E have been drawn.
The force in DE is found to be in compression.
The force in CE is found to be in tension.
A force diagram has been drawn at B.
The force in BD is compressive.
The forces at D are drawn.
The last force, CD is found.