Why is it important to check the magnitude of vectors when adding them?

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Homework Help Overview

The discussion revolves around the importance of checking the magnitude of vectors when adding them, particularly in the context of a problem involving resultant vectors and their units. Participants are exploring the implications of vector addition and the correct interpretation of results.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the correct interpretation of the resultant vector's magnitude and units, questioning why a result is expressed in Newtons instead of meters per second. There is also a focus on verifying calculations and understanding the implications of vector addition, particularly when angles between vectors are involved.

Discussion Status

Some participants have provided clarifications regarding potential typographical errors in the problem booklet, suggesting that the resultant vector should indeed be in meters per second. There is acknowledgment of calculation errors and a recognition of the need to verify results against expected magnitudes.

Contextual Notes

Participants are working with a specific problem that involves vectors at a 90° angle, and there is mention of a scale used for calculations. The discussion highlights the importance of ensuring that the resultant vector's magnitude aligns with the physical context of the problem.

ryanking93
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Homework Statement
Add the following vectors and determine the resultants (length, angle from O)
Relevant Equations
3 m/s. 45° + 5 m/s. 135°
So I've charted the equation above, and received the correct resultant 104.0° I used a scale of 1m/s = 2cm and I get 11.8cm which gives me 23.6m/s but when I look at the answer it is 104.0° / 5.83N

I have no idea why its in Newtons.
 
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Welcome! :smile:
Could you post the original text of the problem?
The value you found is not correct.
 
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Lnewqban said:
Welcome! :smile:
Could you post the original text of the problem?

Thank you. I have attached both the questions and answers I am referencing. The specific question is "C"

And my answer to the question.
 

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Typographical error.
 
OmCheeto said:
Typographical error.

Okay, Thank you. I thought I might be losing it for a minute.
 
ryanking93 said:
Thank you. I have attached both the questions and answers I am referencing. The specific question is "C"

And my answer to the question.
It is an error of the booklet, the resultant vector should be in m/s.
Note that the angle between your vectors is 90°, therefore, you could apply the Pythagorean equation and see that the result can't be 23.6 m/s.
 
Lnewqban said:
It is an error of the booklet, the resultant vector should be in m/s.
Note that the angle between your vectors is 90°, therefore, you could apply the Pythagorean equation and see that the result can't be 23.6 m/s.

Ahhhh I see now! My issue was when I ended up with 11.8cm instead of dividing by 2 I multiplied by 2. As my scale was 1m/s = 2cm. I end up with 5.9m/s.

Thanks a million for the help!
 
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ryanking93 said:
Ahhhh I see now! My issue was when I ended up with 11.8cm instead of dividing by 2 I multiplied by 2. As my scale was 1m/s = 2cm. I end up with 5.9m/s.

Thanks a million for the help!
When adding vectors, it is good to check that the result is not greater than the addition of the magnitude of each independent vector.
You are welcome. :smile:
 
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