Nikita devised the following method of measuring the muzzle velocity of a rifle (Fig. 12-33). She fires a bullet into a 6.023-kg wooden block resting on a smooth surface, and attached to a spring of spring constantN/m. The bullet, whose mass is 7.870 g, remains embedded in the wooden block. She measures the distance that the block recoils and compresses the spring to be 9.460 cm. What is the speed of the bullet? 142.7k