Essure behind a rifle bullet varies inversely with the position x of the bullet along the barrel. thus the acceleration of the bullet may be written as a=k/x where k is a constant, xis in meters and a is in m/s 2. if the bullet starts from rest atx= 7. 5 mm and if the muzzle velocity of the bullet is 600 m/s at the end of the 750-mm barrel, calculate the acceleration of the bullet as it passes the midpoint of the barrel at x= 375 mm.