1. The problem statement, all variables and given/known data A rifle with a barrel length of 56 cm fires a 10 g bullet with a horizontal speed of 350 m/s. The bullet strikes a block of wood locked in position and penetrates to a depth of 13 cm. What resistive force (assumed to be constant) does the wood exert on the bullet? How long does it take the bullet to come to rest? 2. Relevant equations f = m * a d = v * t vf = vi + a * t 3. The attempt at a solution Force of wood on bullet = 4700 (was confirmed correct) f = m * a a = -471154 N How long does it take the bullet to come to rest? I tried D = v * t1 for the barrel .55 = 350 * t1 t1 = 350 / .55 = .0016 seconds For the wood vf = vi + a * t2 0 = 350 - 471154 t2 t2 = 350 / 471154 = .000743 seconds t1 + t2 = .002343 seconds which is wrong.