Should the Z Coordinate Be Included in XY Plane Vector Problems?

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Discussion Overview

The discussion revolves around whether the z coordinate should be included in vector problems specified to be in the XY plane. Participants explore the implications of this requirement in the context of a recent exam question and the expectations set by previous homework assignments.

Discussion Character

  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant questions the professor's grading decision, arguing that the problem clearly stated it was in the XY plane and provided the answer as <-3,4>.
  • Another participant inquires whether previous homework required the z coordinate to be included even when it was zero.
  • A participant notes that their homework typically specified an XYZ coordinate system when applicable, suggesting that the exam question might have been misleading.
  • One suggestion is made to discuss the issue with the instructor to seek clarification and possibly have the point reinstated.
  • Another participant expresses agreement with the initial poster's concerns and emphasizes the importance of seeking clarification when confused about exam questions.

Areas of Agreement / Disagreement

Participants express differing views on whether the inclusion of the z coordinate was necessary in this context. There is no consensus on the appropriateness of the professor's grading decision.

Contextual Notes

Participants reference specific homework problems and grading practices, indicating that expectations may vary based on context. The discussion highlights the potential for confusion in interpreting the requirements of vector problems.

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Hi I didn't post this in homework help, as I didn't feel my question belonged there. If it doesn't belong here, my apologies.

I recently took an exam and it turns out I got the first question wrong according to my professor. The problem states:
"In the diagram four vectors are represented by arrows in the xy plane. Each division represents 1 meter" "What is vector d?"
Because the problem stated it was in the XY plane I put the answer as <-3,4>, but my professor took off a point for not accounting for the z coordinate.

I'd like a second opinion please.

http://gyazo.com/b54c3535fd7fd5f95138e7af3e68d786.png
 
Last edited by a moderator:
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Did your homework questions on this subject usually have you write the Z coordinate even when zero or when the problem was stated to be in an XY plane?
 
Yes, but on our homework questions it would clearly state it was an XYZ coordinate system and include a Z axis. I thought the problem was a trick question to make sure we were paying attention and not writing the z just for the sake of writing it.

Here is a similar homework problem:
http://gyazo.com/4b63e64b66621fa1a50f41cec00146e7.png

I think that problem alone warrants me to the right to question my professors solution.
 
Last edited by a moderator:
I'd talk to your instructor, explain what went on in your mind, and then see if he will give the point back. If he won't, then I'd ask him to change the question to state it was an XYZ plane in order to avoid future confusion. In any case I'd say it's up to him. Of course, if you REALLY want to get into it you can always go to whoever is above him.
 
Permanence said:
I think that problem alone warrants me to the right to question my professors solution.

Personally I agree. Just remember that if you're ever confused on what a question is asking you, ask the instructor or test proctor or whoever.
 
Thank you very much Drakkith. I hate confrontations, but I'll go to her office hours soon. This is resolved.
 

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