The relative speed between the fish and the bird, given that the fish is moving up and the bird is moving downwards is 12 m/s (option C)
How to calculate the relative speed of between the fish and bird?
According to the question given, we were told that:
- Speed of fish = 3 m/s vertically upward
- Speed of bird = 9 m/s vertically downward
- Relative speed between fish and bird =?
The relative speed between the fish and the bird can be calculated as illustrated below:
Relative speed between fish and bird = Speed of fish + speed of bird (since they move opposite)
= 3 m/s + 9 m/s
= 12 m/s
Therefore, we can conclude that the relative speed between the fish and bird is 12 m/s. Thus, the correct answer is option C