/sci/ - Science & Math

translations if they weren't obvious or I couldn't fit in the image:
>aerospace
>biomedical
>chemical
>civil
>materials science
>automobile
>engineering physics
>industrial
>mechanical
>computer
>energy

anyone kind enough to help? awesome coloured pic in return.

1. The problem statement, all variables and given/known data
A step down transformer, 2400/240 V, 50Hz has the following resistance and leakage parameters.
Z1 = R1 + jX1 = 4 + j12 Ω
Z2 = R2 + jX2 = 0.04 + j0.12 Ω

The transformer is operating at 80% of its rated load. The power factor of the load is 0.866 leading.
Determine the induced EMF in the primary side

2. Relevant equations

E = 4.443 f N B A
Ni = Hl = R phi
phi = BA
E = N d(phi)/dt

3. The attempt at a solution
I don't know how to solve for N and phi. It's as if I'm leading nowhere.
So far, I've got

Attempt 1:
a = V1/V2 = 2400/240 = 10
i1 = 2400/(4 + j12) = 60 - j180 = 189.7 cis (-71.57)
but then if I try to use Ni=Hl I get stuck on finding H from B=uH

Attempt 2: Try solving for N with L
L = N^2/R
N = sqrt(LR)
R = 4 + j12
Substitute L = N^2/R into N = sqrt(LR) you just end up with N = N (nothing useful)

Attempt 3: Transfer Z2 from the secondary side over to the primary side

a= 2400/240 = 10
a^2 = 100
Z2' = 100 (0.04 + j0.12) = 4 + j12
Zeq = Z1 + Z2' = 2 (4 + j12) = 8 + j24
Then using Ni = R phi
i = 2400/(8+j24) = 30 - j90 A
R = 8 + j24
Then get stuck on finding phi...

Attempt 4: using V1/V2 = N1/N2
2400/240 = N1/N2
Assume 100 turns in N1, then N2 = 10 turns.
and let phi = i
then E = 4.443 (50) (100) (60-j180) = some massive number in MegaVolts

I've searched and searched in lecture notes for anything to do with the turns ratio, but can't find anything useful.

Please help.

as an engineering science in my first year i plan on doing electrical engineering. Will i ever actually USE chemistry at all?

choose one

I was staring at this picture when dad walked past my room, he walked in and asked who these people are.
I pointed to Einstein and Curie and said you should know who these two are, he said yes.
I then pointed to Planck, Bohr, Lorentz, Schrondinger and Heisenberg and asked again, he said he had no idea.
He asked about what they contributed to science, I told him about quantum entanglement (which he had never heard of before), I told him about the constant debates between Einsten and Bohr about determinism and a probabilistic view of the universe, I also told him about quantum superposition.

He asked about what quantum entanglement proves, I told him that it could be used for long distance communication, possibly even teleportation.

He just nodded and said, good. Then walked off.

Did I ruin my chance to explain science to a deepy religious man or was I right when I said entanglement can be used for communication with 0 time delay

What happened to the great minds? Why are these people the last of their kind?
All we have are trolls like Michio Cocku, and Neil smokedGrass Tyson.

Hey guys i'm a brand new engineering science major and I'm still in pre calculus because of my placement after high school. Do you guys have any places online or books or any resources that can be useful to help me understand calculus 1 before i actually take the course. thanks