Three balls are identical in size, but differ in their masses. Ball A has a mass m; ball B has a mass m, and ball C has a mass 2m. Consider the following cases and determine in which of these linear momentum is conserved. Note that the balls are constrained to move along the x-axis and motion in the positive x direction (toward the right) is indicated with a plus sign. Motion in the negative x direction (toward the left) is indicated with a minus sign.
Case I: Ball A is moving with velocity +v to the left of ball B, which is moving with velocity -v before an inelastic collision of the two balls occurs. The speed of the two balls after the collision is zero m/s.
Case II: Ball B is moving with velocity +4v to the left of ball C, which is moving with velocity +v before an inelastic collision of the two balls occurs. The two balls stick together after the collision and move with a velocity +2v.
Case III: Ball A is moving with velocity +2v to the left of ball C, which is at rest before an inelastic collision of the two balls occurs. The two balls stick together after the collision and move with a velocity +2v/3.