I spent way too long on the drawings. And I got 2400m for the height.Envoytheguy said:The majority of it was OK. I BSed my way through, and my two drawings were a bit dodgy lol
What did you guys get for the Height of the question about the airship powered by a DC? 2400? or 1900 something?
Which was why it was only one markE-Dog said:I had to fight down the lols at that question about how much force is the cable holding in KN.... "duhhhhhhhh...."
it was just the weight force of the car right? i spent ages on that question, i didnt believe that it could be that straight forward lol. then i saw the mark valueE-Dog said:Oh man - Trickier than I anticipated. But overall alright. I had to fight down the lols at that question about how much force is the cable holding in KN.... "duhhhhhhhh...."
damn i got that one wrong; i realised it was weight of the car afterwardsgibson-166 said:it was just the weight force of the car right? i spent ages on that question, i didnt believe that it could be that straight forward lol. then i saw the mark value
yes, my logic prevailed, all be it ill lose at least 6 makrs for drawingsiEdd said:Ah yeah, the drawings were crap. My pictorial was kinda "eh it'll do" job.
I think the water one was half-length. Reason being is the rod is half the density of water, so requires twice the volume of water to displace that volume. Hence, 50mm for a 100mm rod.
I got the same for the multiple choice. And I did the same for the voltage drop, but wasn't entirely sure about it... makes more sense now though.iEdd said:The height would be 1200m if you simply divided voltage by current to get resistance. I think if you put 2400 you forgot to account for 2 wires.
I crossed that out and redid it, accounting for the voltage drop. The circuitry required 195V, meaning 45V could be dropped in the wires, allowing 4.5ohms each. The maximum height was about 225m in the end, AFAIK. Reason being that the circuitry in the airship draws 5A - that means its internal resistance is this, NOT the resistance of the long wires. If you didn't have to account for voltage drop, why would they quote the 195V figure?
Edit: Pretty sure these are correct for multiple choice. Appreciate input:
Yeah but shouldn't you not use 240v because it only draws 195v not 240?iEdd said:Awesome. Also another way to think of it is that if you account for the wires only, then when you reverse the process (V=IR), the whole 240V is dropped across the wires, meaning nothing else can be in the circuit. So yeah I think we did it right.