# Homework Help: Calculate resultants of two forces

1. Jan 27, 2013

### zeralda21

1. The problem statement, all variables and given/known data

Where does the resultant of the two forces act?

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

2. Relevant equations

None really. Basic algebra for calculating resultants.

3. 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.

Last edited: Jan 27, 2013
2. Jan 27, 2013

### 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?)

3. Jan 27, 2013

### zeralda21

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).

4. Jan 27, 2013

### 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?

5. Jan 27, 2013