Calculating River Flow Using Reference Frames

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Homework Help Overview

The problem involves calculating the flow rate of a river based on the travel times of a boat moving downstream and upstream. It relates to the subject area of kinematics and reference frames.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss calculating velocities for both downstream and upstream trips, with some questioning how to relate these velocities to the flow of the river. There is an exploration of using reference frames to understand the problem better.

Discussion Status

Some participants have suggested setting up equations to relate the boat's velocity and the river's flow. There is a recognition of the need to consider the direction of the current when calculating the velocities. Multiple interpretations of how to approach the problem are being explored.

Contextual Notes

Participants are working within the constraints of the problem's data, including the travel times and distances, while discussing assumptions about the boat's velocity relative to the water and the shore.

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A boat takes 3.20 hours to travel 10.0 km down a river, then 6.10 hours to return. How fast is the river flowing?

can someone give some suggestions as to how to do this? I am guessing you use reference frames. thanks in advance.
 
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Use the data you have to find the velocity each way, then you should be able to finish it from there.
 
what am i supposed to do with the velocities? i tried taking the difference of the velocities divided by the difference in time but that was wrong. am i supposed to find the velocity of the boat itself and find it relative to the actual rate the boat traveled?
 
Remember that when the boat is traveling with the current, the velocity of the boat relative to the water plus the velocity of the water equal its total velocity relative to the shore (you were right, this is about reference frames). On the return trip...you guessed it, the velocities are subtracted. Can you set up an equation with one variable to solve for?
 
ahh yes i got it now
basically set up two equations vb + vw = downstream velocity and vb - vw = upstream velocity. find vb (velocity of boat) by adding both given velocities and divide by two. then solve for vw (velocity of water) using either of the equations.
 
:smile: :smile: :smile:
 

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