This is going to sound odd but I am hoping to use physics to defend an allegation made by my ex-wife. She alleges that I threw a knife into my kitchen sink and it bounced up and stuck into the ceiling (in reality I was overseas when the knife was broken by her brother - I'm just hoping to use as many angles of defense as possible). I think I have a basic understanding of the parameters I need to use but I am unsure of how to calculate some of those parameters. I guess it's about working backwards to calculate probability (I am hoping to show that the allegation is implausible). I know I need the mass of the knife and the height from the sink to the ceiling, therefore calculating the energy required for the knife to reach the ceiling. From there I need to calculate the damping effect of both the knife (difficult with an irregular shape made from a mixture of materials) and the stainless steel sink. This will give me the impact force required. I am unsure as to whether, given the required force of the throw, gravitational acceleration and/or terminal velocity would come into consideration. Can anyone help me as to where I proceed from here?