Question

A hypothetical truss comprising weightless members is shown. Assuming tension positive and compression negative, the force in member TU (in kN, rounded off to one decimal place) is \(\underline{\hspace{2cm}}\). 

Hint:

If a joint has only vertical loading and two symmetric diagonals, the horizontal member is always a zero-force member.

Answer 1

Correct Answer: 0

Member TU is horizontal. The 30 kN load at joint U acts vertically downward. Two symmetric inclined members (UV and US) share the vertical load. Their horizontal components cancel each other due to symmetry.
Since no external horizontal load exists:
\[ \sum F_x = 0 \] Thus the horizontal member TU carries no force:
\[ F_{TU} = 0\ \text{kN} \] Final value:
\[ \boxed{0.0\ \text{kN}} \]