237 Finding the resultant of parallel forces acting on both sides of the rocker arm

$R = \Sigma F$

$R = 50 - 40 - 20 + 60$

$R = 50 \, \text{ lb}$       downward
 

$M_O = Fd$

$M_O = -50(6) + 40(2) - 20(3) + 60(8)$

$M_O = 200 \, \text{ lb}\cdot\text{ft}$       clockwise
 

$Rd = M_O$

$50d = 200$

$d = 4 \, \text{ ft}$       to the right of O
 

Thus, R = 50 lb downward at 4 ft to the right of point O.             answer