Pedantic Notations and Exam Questions

A forum set up for physics questions from students in the courses PHYS1121, 1131, 1221 and 1331 at the University of New South Wales. It is intended for questions that cannot readily be answered in class,
either because they fall outside the main syllabus and therefore would be distraction (however interesting) or for other reasons.

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Sans Sanity
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Joined: Sun May 05, 2013 11:47 am

Pedantic Notations and Exam Questions

Postby Sans Sanity » Sun May 05, 2013 12:01 pm

I was going through a past paper where you are meant to calculate the rate of work which gravity is going on an object. Due to the information provided in the question, my results ended up being 1.1x10^8 J/hour to 2 sig.figs. The answer ended up being 2.9x10^5 Watts. I continued my answer to get the latter, which was the correct answer. If I was to use that first answer as an answer in the exam, would I be marked incorrect due to the incorrect notation, or would I be marked correct due to the answer being correct in its own notation?

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joe
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Re: Pedantic Notations and Exam Questions

Postby joe » Sun May 05, 2013 3:07 pm

Rate of work done by gravity ...
1.1x10^8 J/hour


Yours certainly is an unexpected unit. It's a bit misleading here, too because, if ever an object fell for one hour, then the gravitational field would not be constant.

You might lose one mark for giving strange units, but not more: it would depend on the wording of the question and perhaps the generosity of the marking scheme and marker.

In general, while it is possible to write speed as furlongs/hour and surface tensions as gigaslugs per square fortnight, I'd suggest sticking to SI units

Joe


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