Problem 333 | Equilibrium of Parallel Force System

$\Sigma M_{R4} = 0$

$12R_3 = 4 [ \, \frac{1}{2}(12)(400) \, ]$

$R_3 = 800 \, \text{ lb}$
 

$\Sigma M_{R3} = 0$

$12R_4 = 8 [ \, \frac{1}{2}(12)(400) \, ]$

$R_4 = 1600 \, \text{ lb}$
 

 

$\Sigma M_{R2} = 0$

$16R_1 = 13(1600) + 12R_3$

$16R_1 = 13(1600) + 12(800)$

$R_1 = 1900 \, \text{ lb}$           answer
 

$\Sigma M_{R1} = 0$

$16R_2 = 3(1600) + 4R_3 + 16R_4$

$16R_2 = 3(1600) + 4(800) + 16(1600)$

$R_2 = 2100 \, \text{ lb}$           answer