Two lumps of clay approach each other from opposite directions and collide head on inelastically, combing into one large lump after they collide. the first lump has a mass of 0.140kg and has a speed of 3.50 m/s before the Collision. the second lump has a mass of 0.620kg and has a speed of 4.81 m/s before the collison in a direction opposite that of the first lump. what velocity does the combined lump have after the collision?