In your job in a police lab, you must design an apparatus to measure the muzzle velocities of bullets fired from handguns. your solution is to attach a wood block of 1 mass m that rests on a horizontal surface to a light horizontal spring. the other end of the spring is attached to a wall. initially the spring is at its equilibrium length. a bullet is fired horizontally into the block and remains embedded in it. after the bullet strikes the block, the block compresses the spring a maximum distance d. you have measured that the coefficient of kinetic friction between the block and the horizontal surface is μk. you want the maximum compression of the spring to be xmax. what must be the force constant of the spring?