It's been a stressing Tuesday afternoon in the library, trying to understand and figuring out why problems are suppose to be solved this way rather than the other way round. I thought I could clear all my doubts during consultation, but when i was in the library more doubts surfaced. And yeah, I'm crapped up. Damn...



Math...the...mat...tics... Siaaan to the maximum !




How ?! Help ?!

It's not that I do not know how to do, it's how the questions can be twist and turn without you knowing. Okay for example, let us take a look at this question of mechanics of flight:

Calculate the engine thrust required during cruise.

As some of you might know, to find the minimum thrust you must have maximum (L/D). Therefore, CDo = CDi. With these two information, i acquired the Cl and Cd very easily. OK ! Problem solved ! I got the thrust required.

Now here comes the confusing part... The answer turned out to be the other way round, this was how this answer was obtained.

I have the weight of the airplane, density and wing area, and velocity values. Using the formula
i am able to find the Cl value. Ok now i sub this Cl value into another formula in
which i obtained the Cd value. Same as the above, I calculated and this time the answer
seemed to tally with the one as given in the booklet. Damn !

So tell me, which method do you expect to use if you encounter this question when you are in the actual exam ? Haix... I can't wait to see my lecturer to clear this doubt, hopefully he allows both methods to be used. It's not about the workings, it's about you understand the theory behind and thus applying the correct application to solve the question...

Argh here comes the more Fucked up part, my internet just got disconnected. -.-