Engineering Exam Question Missing Information...

Agreed, its a good technique, my other technique is if i come to a question i find too hard, or i make a mistake, i leave a blank page and continue, then if i have time later i'll come back and try to figure out what went wrong.

That way i wont lost 3 questions worth of marks trying to find a mistake in one question.
 
adolf hamster said:
I'd have calculated based on the air required for combustion with no excess. Then if there was a difference between that and the 1400k exit temperature i'd assume that any cooling was caused by excess cool air and work out the excess from the temp difference.

Eg if no excess air gives 2500k heat coming out, then 1100k is being lost to mixing with excess cool air.

If that sort of makes sense, the main assumption would be that heat isn't being lost through the chamber walls.
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This sounds like a good approach but without knowing the physics a little more I couldn't say if it is possible.
 
adolf hamster said:
I'd have calculated based on the air required for combustion with no excess. Then if there was a difference between that and the 1400k exit temperature i'd assume that any cooling was caused by excess cool air and work out the excess from the temp difference.

Eg if no excess air gives 2500k heat coming out, then 1100k is being lost to mixing with excess cool air.

If that sort of makes sense, the main assumption would be that heat isn't being lost through the chamber walls.
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I'd have skipped it about about 2 minutes, gained loads more time for other questions and got 100% for the question when they modify the marks at the end :cool:
 
valkynaz said:
I remember always being told to do this by my teachers at school/college. It's meant to help you get in the right mindset or something. They even recommended we do the exam back to front, spending as much time as we could on the essay parts of exams to score maximum points.
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Always good to propey read the question and check nothubgnconrinues to the next page.

Also good to skip questions which seem insanely hard and come back to them at the end. You can easily spend 30 minutes racking tour brain and panicking in a downward circle. Just move on. Your aim is to answer as many questions as possiblec not answer all questions in order and stop when you are stuck.

You might also find that if you read a question and decide to to skip becuase you have a metal block or some such then your subconcious will work at the problem in 5he background and you will come up with an answer or remember a critical equation or fact while working on the rest of the paper
 
danza said:
Tutor has been emailed. :)

And of course, real world engineering is often far removed (but not so far) from the theoretical in order for the product to function, whilst at the same time being physically possible (we get this a lot at work).
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I had the same in a final year Structural Integrity exam last May, except we were a smaller specialism from mech eng so we were in a different venue and nobody told us of the missing value required to answer the question.

Notified the lecturer and course leader and it was confirmed we weren't told about the mistake. As a result, our marks were based upon method using a required value that we had determined (in this case it was a radius). Didn't affect our results.

As someone said above, sometimes you don't always know the values. You have to use your knowledge to have an educated guess at a starting point and work from there. Almost in an iterative manner, I did similar when working on IC engine simulation.
 
We had one where a question totally threw the whole class. We all got together after the exam and the University sorted stuff out.
The key thing is to act fast, and for the whole class to complain en masse.
 
I've had exams where balance sheets don't balance and computer network multiple choice answers are all wrong. It happens. Some lecturers are just lazy.
 
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