River Flow Rate: Find Answer b in 1.5m/s at 28°

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Homework Help Overview

The problem involves swimming across a river with a specific width while accounting for the river's flow rate. The subject area includes kinematics and vector resolution, particularly focusing on angles and relative velocities.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the formulation of the solution, with one questioning the correctness of their initial sketch and calculations. There is mention of using trigonometric functions to resolve the swimming velocity into components.

Discussion Status

The discussion is ongoing, with participants exploring different approaches to the problem. One participant has recognized an error in their drawing and is reconsidering their method of calculating the river's flow rate.

Contextual Notes

There is a lack of clarity regarding the initial assumptions made in the problem setup, particularly in relation to the angle and the resultant velocities. The original poster has provided multiple choice answers, which may influence the direction of the discussion.

ChloeYip
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Homework Statement


You want to swim straight across a river that is 76 m wide. You find that you can do this if you swim at an angle of θ = 28° from the upstream direction at a constant rate of 1.5 m/s relative to the water. At what rate does the river flow? The angle θ is measured from the river bank (directly upstream is θ = 0° while directly across the river is θ = 90°).
(a) 1.8 m/s (b) 1.3 m/s (c) 1.6 m/s (d) 0.70 m/s (e) 2.1 m/s

Answer:b

Homework Equations


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The Attempt at a Solution


1.5 sin28° = 0.70m/s

How can obtain answer b?

Thanks
 
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How did you formulate your solution attempt? Did you make a sketch? If so, can you share it?
 
Oh thanks...
I just discover my drawing is wrong...
The answer is by v cos theta
 
ChloeYip said:
Oh thanks...
I just discover my drawing is wrong...
The answer is by v cos theta
Okay! It's great that you worked it out yourself!
 

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