AP Test vs My Teacher: Resolving a Vector Problem

[lateralus00]

I had a question regarding the AP test - anyone who knows please answer.

I answered a section of a problem regarding a Vector (asking for direction and magnitude), and my answer was as follows:
802.5N @ -333.5 degrees

The answer was 802.5N @ 26.5 degrees

Any physics teacher should know that -333.5 = 26.5...
Anyways, I got it wrong, however no where in the directions did it state that I needed to use a positive angle.

Others got it correct for simply putting 802.5N @ 26.5 degrees..nothing more.

His logic for taking the points off was because I didn't say "-333.5 degrees above the horizontal"

Would I have gotten this wrong on the AP test? If not I'm going to have a talk with him, because i suspect he's being a jerk.

 

[z-component]

Welcome to PF!

I think it's a good practice to give the angle measurements with respect to the horizontal (x-axis) just because it's arbitrary if you just say "26.5 degrees" without a reference point.

 

[Manchot]

No, they would most likely not take off for that, unless the directions said to specifically keep your angles between 0 and 2*pi.

 

[Tide]

The answer is correct. I would have given credit for it assuming your description of the situation is accurate.

 

[CarlB]

Would I have gotten this wrong on the AP test? If not I'm going to have a talk with him, because i suspect he's being a jerk.

It really depends on who is grading the AP test.

You should never forget that which side of the bread has butter on it. As a student, be assured that your side does not.

Three general rules for education:

(a) The instructor is always right.

(b) The instructor is the one who determines your grade.

(c) The instructor is always right.

The best class to learn these things in is a Social Science class that covers the theory of government. Find out what happens when you disagree politically with the instructor. The lesson, which is far more important than anything you will learn from the textbook, is that might makes right.

Carl

 

[Claude Bile]

If marks were deducted for not providing a reference point for the angle, then other students who did not provide a reference should have had marks deducted also. My impression from the OP was that this was not the case.

It shouldn't be acceptable to lose marks due to marker inconsistancy, but as Carl points out, kicking up a stink may be more trouble than its worth.

Claude.

 

[lateralus00]

thanks for the advice, though i think you're right

those 2 points aren't worth an entire year of him disliking me!

though i do think this is something i can bring up once i graduate to the science coordinator, because this happens all too often with this instructor

..he's a biology major..teaching AP physics, doesn't make sense to me

 

[vanesch]

Any physics teacher should know that -333.5 = 26.5...

Isn't -333.5 degrees MUCH COLDER than 26.5 degrees ?

(you said it was a bio graduate... )

 

[Chi Meson]

The AP readers might take 1 point off of this answer for it NOT following convention of greatest simplification of answers. If a reference direction is not given, it is assumed that the +X axis (or the direction EAST, {back off you sea navigators}) is along 0 degress. So yes -333.5 degrees is the same as +26.5 degrees, but it is perhaps "a less simple" answer. Again, I stress perhaps 1 point would be taken off by the AP folks.