Is There More Than One Way to Solve a Trivial Vector Problem?

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Homework Help Overview

The discussion revolves around a vector problem involving the graphical determination of resultant vector displacements. Participants explore the interpretation of vector components in relation to compass directions, specifically addressing the x and y components derived from given angles and magnitudes.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss different methods of calculating vector components, questioning the correctness of their approaches and the interpretation of the unit vectors i and j in relation to compass directions. There is a focus on whether both answers can be considered valid based on perspective.

Discussion Status

Some participants have provided guidance on the correct interpretation of the components, suggesting that there is a definitive answer based on standard conventions. However, there remains a lack of consensus on the validity of the original calculations presented in the attached image.

Contextual Notes

Participants are navigating the implications of different interpretations of angles and components in vector analysis, with some expressing uncertainty about the correctness of their approaches and the assumptions made regarding the coordinate system.

guyvsdcsniper
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Homework Statement
Graphically determine the resultant of the following three vector displacements: (1) 24 M, 36 degrees north of east; (2) 18 m, 37 degrees east of north; and (3) 26 m, 33 degrees west of south.
Relevant Equations
Vy=Vsintheta
Vx=VCostheta
I got the attached photo from someone who solves physics problems on youtube. As you can see their final answer is 6.7i+16j. I understand how she got these values but I came out with something slightly different. I solved for the x and y components on the opposite side of each vector. So basically I came out with 16i+6.7j. Both answers make sense but I believe it comes down to a matter of perspective.

I searched around on the internet and I see that many people took different approaches to this problem resulting in people either getting my answer or the attached answer.

Are they both technically right? It feels as though that a lot of these physics problems come down to a matter of perspective.
 

Attachments

  • Screen Shot 2021-01-29 at 3.09.31 PM.png
    Screen Shot 2021-01-29 at 3.09.31 PM.png
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quittingthecult said:
Homework Statement:: Graphically determine the resultant of the following three vector displacements: (1) 24 M, 36 degrees north of east; (2) 18 m, 37 degrees east of north; and (3) 26 m, 33 degrees west of south.
Relevant Equations:: Vy=Vsintheta
Vx=VCostheta

I got the attached photo from someone who solves physics problems on youtube. As you can see their final answer is 6.7i+16j. I understand how she got these values but I came out with something slightly different. I solved for the x and y components on the opposite side of each vector. So basically I came out with 16i+6.7j. Both answers make sense but I believe it comes down to a matter of perspective.

I searched around on the internet and I see that many people took different approaches to this problem resulting in people either getting my answer or the attached answer.

Are they both technically right? It feels as though that a lot of these physics problems come down to a matter of perspective.
It depends on how you are relating ##\hat i## and ##\hat j## to compass directions.
The usual would be i for E and j for N.
On that basis, what do you think the i component of "24 m, 36 degrees north of east" is? There is only one correct answer.
It might help if you compare with zero degrees N of E. Does sin or cos give the right answer?
 
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haruspex said:
It depends on how you are relating ##\hat i## and ##\hat j## to compass directions.
The usual would be i for E and j for N.
On that basis, what do you think the i component of "24 m, 36 degrees north of east" is? There is only one correct answer.
It might help if you compare with zero degrees N of E. Does sin or cos give the right answer?
The i component should be the adjacent side of that angle which would come out to be 24*cos(36). Is that correct? I've attached my work as reference (my apologies for it being a bit messy).

So would that mean the original attached image is wrong?
 

Attachments

quittingthecult said:
24*cos(36)
Yes.
The working in the image in post #1 is wrong.
 
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haruspex said:
Yes.
The working in the image in post #1 is wrong.
Thank you!
 

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