Lets assume that a signature of guns is the velocity of its built. A built mass is 2g in average and very close in different guns. You are the detective assigned for a crime scene investigation. You realize that there has been a shooting involved. The built has made a whole 0.30m deep in the wall. If the resistive force of the wall on the built is 900N. You also realize that a 5kg sign hanging from the ceiling has a dent on it and has made a small scratch on the wall. If the gun was shot parallel to the wall what is the velocity of the built before hitting the sign? I have no clue where to start or even what the question is asking....any help at all would be really appreciated. Thanks. The attachment is the original problem with figures.