In Fig. P-231, the moment of a certain force F is 180 ft·lb clockwise about O and 90 ft·lb counterclockwise about B. If its moment about A is zero, determine the force.
Moment about B
Substitute xFy = 180 to the above equation
Thus, F = 75 lb downward to the right at θx = 36.87° and x-intercept at (4, 0). answer