Answer:
The boat's velocity relative to Earth is 3.91 m/s.
Explanation:
Given;
speed of ferry due north,
= 2.5 m/s
speed of the river to the east,
= 3.0 m/s
The boat's velocity relative to Earth is given by;

Therefore, the boat's velocity relative to Earth is 3.91 m/s.
Nothing on that list of choices is a requirement.
I believe it reflects purple light.
Answer:
400 m/s
Explanation:
If it is moving at a velocity of 80 m/s from rest, then after 5 s it would be at 400 m/s.
80 x 5 = 400