Homework Help: How do I know which direction the horizontal force acts

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1. Apr 30, 2015

DaiRSquared.

1. The problem statement, all variables and given/known data
I am to find the reactions of a 3 pin frame.

2. Relevant equations

3. The attempt at a solution
So how do I know which direction to label the horizontal reactions? In the diagram HA and HF are in the same direction, I was under the impression that reactions are opposite to applied force.

I have no problems calculating a solution once i know which direction the reaction occurs.

2. Apr 30, 2015

SteamKing

Staff Emeritus
Uhh, looks like someone has drawn in the direction of the horizontal forces at pins A and F.

This is why PF Rules request that posters provide a complete description of the HW problem and use of the HW template.

3. Apr 30, 2015

DaiRSquared.

Yes that was me. I know the method to calculate a solution providing I know which directions the horizontal reaction forces act.

My question was how do I know which direction the reaction forces act or what bit of information in that diagram tells me that HA and HF both act to the Right.

4. May 1, 2015

donpacino

If you draw the forces in the wrong direction, you will simply get a negative number in your answer!

5. May 1, 2015

DaiRSquared.

I have already solved my problem and would have marked it solved if i knew how. Your answer was the one I was looking for, thank you for taking the time to read the problem and reply.