# Moments of forces

1. Nov 17, 2013

### anthonyk2013

Are my calculations for R1 correct.

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• ###### space diagram 14-11 02 001.jpg
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2. Nov 17, 2013

I don't understand what's R1,Is it the force or the moment?Can you please write the calculations in the editor?It's difficult to read it

3. Nov 17, 2013

### anthonyk2013

sorry about poor hand writing, not sure how to use editor.
hope image is clearer now.

R1 is a force.

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• ###### force 17-nov 001.jpg
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4. Nov 17, 2013

### haruspex

I don't think you have the horizontal distances right. Triangles E and G are isosceles, yes? How are you calculating the horizontal displacement to the vertical load?

5. Nov 17, 2013

### anthonyk2013

yes E and G are isosceles and if you split D in half you get two more isosceles, draw a vertical line R1 to the pin on the left the distance is 2 square root of 3.

10KN acts down from B on that vertical line and on graph paper its 1/2 root of 3.

10 KN acts down from CH to vertical line and the distance is 1 1/2 root 3.

should I be using the force acting at 45deg at B along the line EF?

6. Nov 17, 2013

### haruspex

you seem to be assuming that the vertical line through the top left pin is halfway to the midpoint of the whole structure. It isn't. Fill in as many lengths and angles as you can in triangles D and E.

7. Nov 18, 2013

### anthonyk2013

Thanks, I'll give that a go.