Engineering Statics

C-7


Four ropes are attached to a crate and exert the forces shown. If the forces are to replaced with a single equivalent force at a point on line AB, determine the equivalent force and the distance from point A to the point of application when a is 30°.

The forces applied to the system can be replaced by a single force along line AB at some distance 'd' from point A.
The sum of x-components of all forces is found.
The sum of y-components of all forces is found.
The resultant can then be written as the vector sum of the x and y 
forces.
&quote;d&quote; can be found by picking any point (most conveniently along AB) and 
taking moments about that point.
Dividing by the coefficient for d, allows us to calculate d.