What would the Free Body Diagram of a Trebuchet look like?

[Physics Student 1]

What would the Free Body Diagram of a Trebuchet look like (FOR THE SYSTEM)? Would it be comparable to a see saw/ teeter totter? I am aware of some of the forces at play, but I feel there is some I am missing.

 

[Simon Bridge]

There is not one - the trebuchet is a composite system so you need multiple fbd's to describe it.

 

[CWatters]

What Simon said.

To solve some systems you have to draw multiple FBDs (typically one per component part). Write equations for each and then solve a set of simultaneous equations.

I found an analysis here..
http://www.real-world-physics-problems.com/trebuchet-physics.html

Note that it contains a lot of diagrams and not all are Free Body Diagrams. Typically they have "schematics" showing a few parts and how they are interconnected (definitions of angles etc) then they draw a "free body diagram" for the just the part they are analysing.

 

[Physics Student 1]

What Simon said.

To solve some systems you have to draw multiple FBDs (typically one per component part). Write equations for each and then solve a set of simultaneous equations.

I found an analysis here..
http://www.real-world-physics-problems.com/trebuchet-physics.html

Note that it contains a lot of diagrams and not all are Free Body Diagrams. Typically they have "schematics" showing a few parts and how they are interconnected (definitions of angles etc) then they draw a "free body diagram" for the just the part they are analysing.

That to me is very hard to understand... Do you or anyone else know the basic forces that act on a trebuchet and in which direction in the system? i.e. force of gravity, force of friction, force of air resistance etc. I just need a simplistic (but not too simplistic) version to show to my class for a presentation.

 

[berkeman]

That to me is very hard to understand... Do you or anyone else know the basic forces that act on a trebuchet and in which direction in the system? i.e. force of gravity, force of friction, force of air resistance etc. I just need a simplistic (but not too simplistic) version to show to my class for a presentation.

Since this is for your schoolwork project, how about you show some effort and make some sketches showing how a trebuchet works?

 

[Physics Student 1]

Since this is for your schoolwork project, how about you show some effort and make some sketches showing how a trebuchet works?

The teacher encouraged that we go to forums for help. I did attempt at free body diagrams for the trebuchet and every time I tried my teacher said I was wrong. He also said it was very complicated, past my grade level. His words were that the internet is a valuable resource and I should use it to find and learn about the free body diagram of a trebuchet. I just simply wanted to see one I could understand and explain to my class.

 

[berkeman]

The teacher encouraged that we go to forums for help. I did attempt at free body diagrams for the trebuchet and every time I tried my teacher said I was wrong. He also said it was very complicated, past my grade level. His words were that the internet is a valuable resource and I should use it to find and learn about the free body diagram of a trebuchet. I just simply wanted to see one I could understand and explain to my class.

Whelp, here at the PF, we help students learn how to learn. Maybe let your instructor hear that phrase -- might be good for them to think about it some.

So please show us all of your work. We cannot spoonfeed you solutions to your homeowrk. As long as we see a lot of effort on your part, we are happy to offer hints and tips and ask probing questions to help you figure out your homework.

Please post your work, or this thread will be closed. Thank you.

 

[CWatters]

The teacher encouraged that we go to forums for help. I did attempt at free body diagrams for the trebuchet and every time I tried my teacher said I was wrong. He also said it was very complicated, past my grade level. His words were that the internet is a valuable resource and I should use it to find and learn about the free body diagram of a trebuchet. I just simply wanted to see one I could understand and explain to my class.

If the link I posted above is too difficult for you can I suggest you look at a Catapult or Mangonel that doesn't have a sling? or start by explaining a Catapult and then conclude by pointing out that a trebuchet is more complicated because it has a sling for which another FBD is needed.