# How'd everyone go? (1 Viewer)

#### megabakedpotato

##### Member
you are all wrong lol the back sprocket turned 3 times for every pedal revolution, straight up that means the vr is less than .33....

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#### iRuler

Engineering is probably harder, but I dont think it scales that well.

#### jgalpin

##### New Member
Not necessarily, it said assume 100% efficiency, so MA = VR (MA / Vr = 1) i had some bullshit answer of like 6.25 iduno

#### megabakedpotato

##### Member
Not necessarily, it said assume 100% efficiency, so MA = VR (MA / Vr = 1) i had some bullshit answer of like 6.25 iduno
lol I did it and checked it many many times and I am 100% sure it was .138

#### tanazeftino1

##### New Member
with the milliamps question 0.025 amps converted is 25 amps. don't you guys know how to use google?
im not sure what i put thought because i remember if i changed it from 25 to 2.5 or 2.5 to 25 :S

#### elvishtears

##### Member
with the milliamps question 0.025 amps converted is 25 amps. don't you guys know how to use google?
im not sure what i put thought because i remember if i changed it from 25 to 2.5 or 2.5 to 25 :S
I think the question asked to find the current of the system, so what you were supposed to do was minus the 2volts that the light bulb used from the power supplies 18volts. Using V= 16 and resistance as 800ohms I ended up getting 20mA

#### megabakedpotato

##### Member
I thought it asked for the current used by the lightbulb?

#### jgalpin

##### New Member
The voltage of the cell is 18V, the lightbulb uses up 2V, therefore the final voltage is 16V, sub this into the equation and you get 0.02AMPS. Multiply this by 10^3 and you get 20mA. NOT 2.5 sorry

#### alen180sx

##### Member
I think the question asked to find the current of the system, so what you were supposed to do was minus the 2volts that the light bulb used from the power supplies 18volts. Using V= 16 and resistance as 800ohms I ended up getting 20mA
The voltage of the cell is 18V, the lightbulb uses up 2V, therefore the final voltage is 16V, sub this into the equation and you get 0.02AMPS. Multiply this by 10^3 and you get 20mA. NOT 2.5 sorry
+1

#### alen180sx

##### Member
lol I did it and checked it many many times and I am 100% sure it was .138
How did you work it out?

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#### megabakedpotato

##### Member
How did you work it out?
Well velocity ratio is distance effort/distance load. So you work out the ratio of sprocket circumferences which was 3, so the circumference of the back wheel (600pie) will move around 3 times every pedal revolution (1800pie). So 1800pie is your distance load and then the distance of the effort is the circumference of one pedal rotation. #### dydx

##### Member
The voltage of the cell is 18V, the lightbulb uses up 2V, therefore the final voltage is 16V, sub this into the equation and you get 0.02AMPS. Multiply this by 10^3 and you get 20mA. NOT 2.5 sorry
Yep! +1. And yes i got 414W for the belt thing. I found the paper much more difficult compared with other years. The "draw the laminated macrostructure" or whatever the question was like ....

#### jgalpin

##### New Member
Haha yew ! solid effort mate, the macrostructure for the laminated i did laminated glass with two sheets of glass and a polymer film inbetween the two. The problem that alot of people had would've been differentiating between MACRO and MICROstructure. Im guessing i got around 82% ish... so im fairly happy

#### jgalpin

##### New Member
For the power of the belt i had P= Force times Velocity, my velocity was 0.877777 and force was mgsin(theatre) cant remember my final answer though, what was the dimensions and weight> 115kg?

#### dydx

##### Member
For the power of the belt i had P= Force times Velocity, my velocity was 0.877777 and force was mgsin(theatre) cant remember my final answer though, what was the dimensions and weight> 115kg?
you don't use any angle. P = Work/time, Work = PE + KE but KE = 0 as we assume the guy with his trolley are stationary and using the escalator. Therefore Work = PE = mgh where m = 115, g = 10, h = 9 and t = 25. Sub all into calculator and you get it 414W.

#### jgalpin

##### New Member
But power = force times velocity?

#### jgalpin

##### New Member
But power = force times velocity?

#### dydx

##### Member
But power = force times velocity?
There are many formulae for power, just use the formulae sheet provided.

#### isman

##### New Member
I said A, electrolytic reaction because B was worded as "stress corosion cracking" not "stress cracking corrosion"
It couldnt be the stress option as the piece was cold-rolled, so the stress is uniform

As for multiplexing, two of the optimum examples were multiple bandwidths in optical fibres and different radio frequencies in FM radio