Question

For the truss shown in the figure, the magnitude of the force (in kN) in the member SR is

• A. 10
• B. 14.14
• C. 20
• D. 28.28

Answer 1

The correct option is C 20

$R_P+R_Q=30kN$

$\sum M_P=0$
$30\times 2=R_Q\times 3$

$R_Q=20N$
$R_P=10N$

Using method of section
Considering moment about point T, which is zero

$R_Q\times 1=F_{RS}\times 1$

$F_{RS}=R_Q=20N\text{compressive}$