Summary of solution method
Sum horizontal and vertical components of forces about A,
and use these components to find torque about O. This is straight-forward and lends to
systematic calculations.
A. resolve forces F1=200 and F2=30 into horizontal and
vertical components, using a table
Force, F
Fx=Fcos(theta) Fy=Fsin(theta)
F1=200 200*(4/5)=160 200*(3/5)=120
F2=30
30*(1/2)=15 -30*(sqrt(3)/2=-25.981
SUM 175 94.019
B. Take moments about O
(clockwise positive)
Torque, To
=Fx*y -Fy*x
=175*0.25 -94.019*0.425
=+3.792 N-m (clockwise)
