# Point of application of resultant force from bound vector forces

1. May 1, 2014

### fog37

Hello Forum,

in the case of two or multiple free vectors, it is easy to determine graphically (head-tail rule) the resultant vector (magnitude and direction). The resultant vector is also a free vector.
A free vector is actually an infinite number of vectors with the same magnitude and direction but different points of application (equivalence class)

In the case of bound vectors, the point of application matters. For example, if an object has two different forces applied at different points on the extended object. How do we calculate the point of application or the line of action of the resultant force which is the sum of the two applied forces?

Is it possible?
thanks,
fog37

2. May 1, 2014

### paisiello2

You calculate the location of the resultant R relative to some fixed point x such that:

Rx = ∑Fixi

I don't really understand your definitions of free and bound vectors as I have never heard those terms before.