Question

A truss hinged at A and supported on rollers and D is loaded as shown in the figure below.The force in member BC is

• A. 6.6

Answer 1

The correct option is A 6.6

The reaction at roller D is perpendicular at roller support,since angle ${45}^{\circ }\text{so}{R}_1=R_2$

Taking moment about point A

$5\times 3+2\times 6=R_1\times 9-R_2\times 4$

$R_1=R_2=5.4kN$

Cutting at section 1-1 and taking moment about F

$F_{BC}\times 4=5.4\times 6-2\times 3$

$F_{BC}=6.6kN$