Calculate resultants of two forces

[zeralda21]

Homework Statement

Where does the resultant of the two forces act?

http://i.imgur.com/CBO8fi2.jpg

Homework Equations

None really. Basic algebra for calculating resultants.

The Attempt at a Solution

First off, I have tried to calculate the x and y components of the resultant, call it R. Here I think that R_{x}=0 (both forces are vertical) and R_{y}=-20 (net force in the y-direction). So the resultant is:

R=R_{x}+R_(y} = 0x-20y with magnitude of 20N. However, I am unable to understand how the lengths will help me.

 

[Simon Bridge]

The question wants you to replace the two forces at different distances with one force that has the same effect. So - what is the effect of each force as drawn? (Hint: what is special about point A?)

 

[zeralda21]

The question wants you to replace the two forces at different distances with one force that has the same effect. So - what is the effect of each force as drawn? (Hint: what is special about point A?)

That is what I have tried to do actually. I have replaced them with one downward force with magnitude 20N. But I don't know where it is located.

What is special about point A? Well, not sure. There must be a force to compensate the downward force but that is done by the beam(object).

 

[Simon Bridge]

20N is what you'd get if the forces acted along the same line.
Do they?

Won't each of the two forces create a moment about point A?

 

[zeralda21]

20N is what you'd get if the forces acted along the same line.
Do they?

Won't each of the two forces create a moment about point A?

Yes, I suppose. I will have to think a little bit about this one before I answer. Not sure about the theory yet.