I am taking a physics modeling class and for our projects we need to add in some element to our physics engine that is unique and different. I choose to model the deformation of objects as a result of collisions. For clarification, When things bounce, I want to know by how much do they deform and to model the impulse and energy lose. My question: I Would like to know any references to equations and or the equations that represent the energy loss and by how much the object deforms so i can have an idea of what parameters i would need to give my objects. I am currently looking into youngs modulus, coefficient of restitution, stress, elastic collisions and more, but i am having trouble finding the correct equation at the moment. And insight and help is always appreciated, thanks for your time and patience.