# Frequently Asked Questions

**I am building a trebuchet for a school project. Can you help me design my trebuchet?**

No. If you have a specific question, I will usually answer it, but I will not do any general design or optimization work for you.

**Can you give me the equations for a trebuchet?**

I have the equations of motion for a trebuchet in the Equations of Motion section. I would suggest working through this Example Problem to understand the basics of how the equations work first. I have done my best to make the explanation of the equations easy to follow, but they do involve some linear algebra and some fairly lengthy differential equations.

**How close are VirtualTrebuchet's predictions to reality?**

In general, VirtualTrebuchet will over predict the performance of a trebuchet by some amount because it ignores things like friction. You can look at the User Projects page to see how VirtualTrebuchet's predictions have compared to some real trebuchets that VirtualTrebuchet users have made. To get a good prediction from VirtualTrebuchet, you need make sure you understand all the input, and use accurate values. If you put garbage in you will get garbage out.