Finding the Hypotenuse with the Given Vector

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Homework Help Overview

The discussion revolves around finding the hypotenuse of a triangle formed by vectors, specifically in the context of vector addition and the sine law. The original poster expresses uncertainty in their approach to calculating the resultant vector and subsequently the hypotenuse.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss constructing a parallelogram to visualize the vectors and consider using the sine law to find the unknown force. There are questions about how to set up the problem correctly and clarify the use of angles.

Discussion Status

The conversation is active, with participants offering various methods to approach the problem. Some guidance has been provided regarding the use of the sine law and constructing a parallelogram, but there remains a lack of consensus on the best method to proceed.

Contextual Notes

There is mention of confusion regarding the setup of the problem and the application of geometric principles, indicating that some foundational knowledge may be assumed or missing.

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Here is the link to the problem http://imgur.com/MGcfdr7


I'm not really sure how to approach this. I initially thought you would get the resultant vector by doing 125cos(38) and that gave me 98, which I then divided by the cos(45) to get the hypotenuse, or F2, which gave me 138.6. It says that this isn't the right answer so I'm not sure what to do.
 
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Did you try to construct the parallelogram first?
 
sevag00 said:
Did you try to construct the parallelogram first?

No, how would I go about solving for F2 with that?
 
By using sine law. You have two angles and F1.
 
sevag00 said:
By using sine law. You have two angles and F1.

Sorry, is there anyway you could set this up for me? I don't really understand what you're saying.
 
Untitled.png

By using sine law you can easily get F2.
 
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sevag00 said:
Untitled.png

By using sine law you can easily get F2.

Oh awesome, thank you! Just got it after digging through my memories of old geometry classes. Forgot about the angles flipping and all that jazz. Thanks for everything
 
Here's another way which gives the same answer. Determine the components of the two forces in direction across the channel. They must be equal in magnitude and opposite in sign in order for the rear of the boat not to move in the cross channel direction.

Chet
 

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