To solve this problem, we can use the principle of conservation of momentum, which states that the total momentum of a system remains constant if no external forces act on the system. The momentum of an object is given by the product of its mass and velocity.
Initially, the total momentum of the system is zero, since the canoe and hunter are stationary. After the hunter throws the spear, the total momentum of the system is still zero, since there are no external forces acting on the system.
Let v be the velocity of the canoe and hunter immediately after the spear is released. The momentum of the hunter, canoe, and spear before and after the throw can be expressed as follows:
initial momentum = 0
final momentum = (75 kg + 10 kg + 0.72 kg) * v
Using the principle of conservation of momentum, we can set these two expressions equal to each other and solve for v:
0 = (75 kg + 10 kg + 0.72 kg) * v
v = 0 m/s
Therefore, the velocity of the canoe and hunter immediately after the spear is released is 0 m/s.