A fisherman and his rowboat have a combined mass of 125 kg. Standing in the motionless boat in calm water, he tosses out a 5 kg rock from the back of...

A fisherman and his rowboat have a combined mass of 125 kg. Standing in the motionless boat in calm water, he tosses out a 5 kg rock from the back of the boat, with a velocity of 5 m/s. What will be the resulting speed of the boat?