1. The problem statement, all variables and given/known data Hello and thank you for reading my question. I am attempting to calculate what effect on a wall has an impact (a car impact or as in my theoretical calculations a punch) of an object into it. With effect I mean how strong impacts can a wall a, survive and b, stay undamaged. Since car crashes deal with too great numbers I have chosen as an example for calculations a punch Known data: a = 9 m/s2 v = 7 m/s m = 4 kg Ek = 98 J S (impact area) = 60 cm2 Wall thickness = 10 cm 2. Relevant equations F = ma Ek = 1/2 mv2 P = F/A a = 1/2 S/t2 3. The attempt at a solution I have gathered a large ammount of data on concrete, brick, steel and mortar strength and fatigue limit. From what I know F = ma is only valid for stationary objects (like the force of me standing on a floor) but not for impacts. I calculated the kinetic energy of the punch but I don't know how to calculate the Force of the impact from it. Also, are the Force and the following pressure and stress from the force the only factors relevant in such an impact into a wall? Another problem is that while I know how to calculate surface pressure of the impact, I don't know how to calculate internal stress. The equations are Fx/S, but I don't know how to acquire either of these variables. I also don't know what kind of stress a punch (or car crash) is, is it shear stress or flexural stress?