Final answer:
The speed of the larger fish after it swallows the smaller one, according to the conservation of momentum, is approximately 0.83 m/s, which would be rounded to the nearest option, 1 m/s.
Step-by-step explanation:
The subject of this question is Physics, specifically related to the principle of conservation of momentum in the field of mechanics. When the 5-kg fish, moving at 1 m/s, swallows a 1-kg fish at rest, the total momentum of the system before the event must equal the total momentum after the event because there are no external forces acting on it.
The initial momentum of the system is the momentum of the 5-kg fish since the smaller fish is at rest and has zero momentum. Therefore, the initial total momentum is: (5 kg) × (1 m/s) = 5 kg·m/s.
After swallowing the smaller fish, the total mass is now 6 kg, and we assume no momentum is lost to other forces since the question doesn't specify any. We can calculate the final speed (v) using the conservation of momentum:
Initial total momentum = Final total momentum
5 kg·m/s = 6 kg × v
Solving for v gives us: v = 5/6 m/s ≈ 0.83 m/s, which is not one of the options given. If rounding to the nearest whole number, we would choose 1 m/s as the closest available answer.