This project is a bow and arrow shooting simulation. The bow and the arrow is based on a mass/spring system. The string and the bow itself have springs attached to it so it can move realistically when an arrow is shot out. The string will semi-vibrate and the bow limb will straighten realistically when an arrow is shot out.
Here's an image of the bow and arrow lock and loaded. The spring particles are hidden.
This is what it looks like when an arrow is shot out of the bow. Spring particles are shown.