How far downstream has the boat moved?

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The discussion revolves around calculating how far downstream a boat moves while crossing a river. The river flows east at 1.80 m/s, and the boat travels north at 9.0 m/s. To determine the downstream displacement, the time taken to cross the 400-meter width of the river is first calculated, which is approximately 44.44 seconds. The correct method to find the downstream distance is to multiply the river's velocity by this time, not divide. The problem is resolved by recognizing that distance equals velocity multiplied by time.
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[SOLVED] How far downstream has the boat moved?

I can't figure out the last part of this question. It's probably very simple and I'm just over looking it. The answers in part A are right. I just don't know how to get part B.

A river flows due east at 1.80 m/s. A boat crosses the river from the south shore to the north shore by maintaining a constant velocity of 9.0 m/s due north relative to the water.

(a) What is the velocity of the boat relative to shore?
9.178 m/s
78.69° (north of east)


(b) If the river is 400 m wide, how far downstream has the boat moved by the time it reaches the north shore?
m
 
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1. Find out the time the boat takes to traverse the 400 meters in the northern direction, at speed 9 m/s

2. Then find out the boat's (eastern) dowstream displacement in the same time .
 
So to fine the time it takes the boat to go 400 meters at a speed of 9 m/s. I divided 400/9.0 and got 44.4444s.

Then I thought to find the downstream displacement given that time you would just divide the 44.444s/(1.8m/s)? But that's wrong and I don't know what else to do?
 
What is distance?

Velocity MULTIPLIED WITH time!
 
SOLVED thanks...sorry for some reason I thought you divided it.
 

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