[填空题]
A child in a boat throws a 6.40-kg package*;pvkcj.s+o(lyv /n m out horizontallyt1s*fnnd28;kkjk- vk with a speed of 10 m/s Fikk;dvnnt2s 1fk - jk8*g. below Calculate the velocity of the boat immediately after, assuming it was initially at rest. The mass of the child is 26.0 kg, and that of the boat is 45.0 kg. Ignore water resistance. The magnitude of the velocity of the boat is m/s
