A lumberjack (mass = 98 kg) is standing at rest on one end of a floating log (mass = 210 kg) that is also at rest. The lumberjack runs to the other end of the log, attaining a velocity of +2.8 m/s relative to the shore, and then hops onto an identical floating log that is initially at rest. Neglect any friction and resistance between the logs and the water. (a) What is the velocity of the first log just before the lumberjack jumps off? (b) Determine the velocity of the second log if the lumberjack comes to rest on it.