Question

a boat is headed with a velocity of 18 meters/second toward the west with respect to the water in a river. if the river is flowing with a velocity of 2.5 meters/second in the same direction as the boat. what would be the magnitude of the boat’s velocity?

Answer 1

both the boat and swimmer are going in the same direction, west.
The net velocity the boat is traveling is then:
18 m/s + 2.5 m/s = 20.5 m/s

The magnitude is the hypotenuse of the components but there is only an x component so magnitude = 20.5 m/s

Answer 2

Answer: Hi!

You know that the boat has a velocity of 18m/s with respect to the water, and the water has a velocity of 2.5m/s.

Both velocities are in the same direction.

Now, if you are standing in the shore, you have a velocity of 0m/h, then you will see the boat moving with his velocity with respect to the water plus the velocity of the water:

this is V = 18 m/s + 2.5m/s = 20.5m/s

Where the addition is direct because both vectors are in the same direction.