A 5.0 g bullet leaves the muzzle of a rifle with a speed of 320 m/s, What force (assumed constant) is exerted on the bullet while it is traveling down the .82 m long barrel of the rifle? This is what I have so far. : [. (320)^2/(2*.82)=t 320/t=a a= 62439 62439*.005 =312 The back of the book is 310. What did I do wrong?