Standard operating procedure short form for SOP. This idea must be adhered to if you want success in Forces.
1. Draw the free body diagram of the rigid body and identify the forces acting on it.
2. If unsure about its direction, indicate its x and y component .
3.Take moments about the point where the forces are unknown, which always turn out to the point where you are unsure about the direction.
4. Apply summation of force in the x and y direction, to find more unknowns.
5. Use pythagoras theorem to find the resultant force from its compoments , angle can be found by trigonometery.
Common reasons for failure to acheive right answer
a) Resolve to get perpendicular distance is preferable to resolving forces .
b) Mathematical error in finding perpendicular distances.
c)Omitting some forces that are present.
d) Take moments about the wrong point ,O.
e) Not all weights act in the centre , some are non-uniform body.
