Question

For the truss loaded as shown in figure, force in the member AC is

• A. $\sqrt{2}$ kN compression
• B. $\frac{\sqrt{3}}{2}$ kN compression
• C. $\frac{\sqrt{3}}{2}$ kN tension
• D. $\sqrt{2}$ kN tension

Answer 1

The correct option is D $\sqrt{2}$ kN tension

Using the method of sections, let the section line pass through AD, AC and AC and BC. Assuming forces in the members AD, AC and BC to be tension, using $\sum F_H=0$.

$P=F_{AC}cos{45}^o$

$F_{AC}=\frac{P}{cos{45}^o}=\sqrt{2}$

(When a member is in tension, the force of the member on the joint will be towards the member).