A 100-g bullet is fired from a rifle having a barrel m long. Choose the origin to be at the location where the bullet begins to move. Then the force (in newtons) exerted by the expanding gas on the bullet is +x x^2, where x is in meters. (a) Determine the work done by the gas on the bullet as the bullet travels the length of the barrel. (b) What If? If the barrel is m long, how much work is done, and (c) how does this value compare with the work calculated in part (a)?