# Homework Help: Pipes and forces

1. May 23, 2006

### TSN79

The drawing below shows two pipes lying on top of eachother. Forces act on the different contact points, and I am to determine these as a result of the pipes' weight G. I'm able to do this graphically, but not by calculation.

Next up is a similar problem, I'm to determine the forces at A and B, where B is a roller. Here I'm able to do it analytically, but not graphically.

If someone could help me I'd really appreciate it

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Last edited: May 23, 2006
2. May 23, 2006

### vsage

I'm not quite sure what you mean by the second problem so I will try and point you in the right direction on the first: Consider each pipe as a free body and recall that you can sum up forces whose lines of action pass through a common point which, because I am assuming no friction (because you didn't mention any) and the fact that all surfaces are tangential, is the center of each pipe.

3. May 23, 2006

### Hootenanny

Staff Emeritus
RE: Second Question
Looks like a simple torque questio to me. What do you mean by a 'roller' at B? Which way can it rotate?

~H

4. May 23, 2006

### Cyrus

A roller is a type of connection. Just terminology. It only has a normal force.

5. May 23, 2006

### Hootenanny

Staff Emeritus
Ahh, thank you cyrus. I apologise for my ignorace; I've never heard of the term before, it is a term specific to engineering?

To TSN
In light of cyrus' information, this question is definatly a simple torque question.

~H

6. May 23, 2006

### TSN79

I know it's a question of torque, but I can't figure out how to solve it graphically. In a graphical solution all the forces need to make an enclosed polygon, which you can use to measure the length (and therefore their magnetude). But here I can't seem to make that work.

7. May 23, 2006

### Hootenanny

Staff Emeritus
This method does not work with torques I'm afraid. Is it a requirment that you solve it graphically?

~H

8. May 23, 2006

### TSN79

Well, the book says to find the reactions by A and B graphically...there is no way?

9. May 25, 2006

### Hootenanny

Staff Emeritus
I Suppose one could measure the distances and length of F to find the torqures involved but this still would required some calculation, would this be considered graphically by your book?

~H

10. May 25, 2006

### civil_dude

For the second problem, you will need to know or then assume a distance from A where the force is located before you can solve the problem.

11. May 26, 2006

### Hootenanny

Staff Emeritus
Thats what I meant when I said measure. That is ofcourse assuming that the diagram is drawn to scale.

~H