another one!! An indestructible bullet 1.86cm long is fired straight through a board that is 8.1cm thick. the bullet strikes the board with a speed of 452 m/s and emerges with a speed of 298 m/s. what is the average acceleration of the bullet through the board? answer in units of m/s^2 what would the length of the bullet and the width of the wall be used for in a kinematic equation? I know 452=v. and 298=v ...... or is that wrong?