1. The problem statement, all variables and given/known data For an extra credit assignment I was given two things I needed to find: 1) The acceleration of an arm when it is breaking a board (like in karate) 2) How physics relates to the breaking of the board 2. Relevant equations This is my first year in high school physics and we just finished our second unit. The only equations I have learned and most likely relate to this are... d=vit + 1/2at(squared) vf(squared)=vi(squared) + 2ad vf=vi + at v=d/t a=v/t 3. The attempt at a solution Because I was given no variables I'm not really sure how to approach this problem. With the equations I do know I'm not really sure what I would put in for time or distance without it being given. Any help would be greatly appreciated. Thanks!