An arrow of mass 20 grams is shot horizontally into a bale of hay with a velocity of 60 m/s. It penetrates a debpt of 20 CM before stopping. What is the average stopping force acting on the arrow? I've been doing W = -F*D W = -(ma)*d I'm finding a by using a kinematic equation, v (final ) ^2 = v (initial ) ^ 2 + 2 a (delta) x. The answer I'm getting is 360 N, but that is not the correct answer. Any ideas?