Parallel voltage sources circuit

Femme_physics

Ah, I see the errors of my ways

I know what to do! *rubs hang together in an evil fashion*

Let me find Ptotal first. Then I shall have the answer, and all the smurfs will be mine!!!!

((PS. Rtotal ends up being 6.33333 ohms ))

I like Serena

Very true!

I intended to ask for the power dissipation in the 4 ohm resistor that is between A and B.



This looks *almost* like a Norton equivalent circuit!

I give you the smurfs. All of them are yours, you *evil* you!
Total power and domination!

Btw, the total power is the sum of the powers dissipated in each of the 3 resistors (I get 259 W).

Femme_physics

Easy peasy!

P2 = 2 x 5.211^2 = 54.31 [W]

Muwahhaahahhah!!!!

You mean
Pt = Power dissipated in resistor 1 +Power dissipated in resistor 2 + Power dissipated in resistor 3?

In which case, I was aware of that!

And I did get the correct result, yes?

I like Serena

Let me see...

We got a total power of 258.65 W.
Subtract 199.46 W from your previous result.
Subtract another 54.31 W that you just got.

That leaves.... 4.88 W for the 4 ohm resistor between A and B.
Yes! That's it! You got it!

Femme_physics

w00000000000000000t

You rock!


I'll probably do the other one tomorrow^^ You're incredible, ILS!!! This is pretty fun for me, I don't know about you You're a life saver. I'm pretty stressed about term B in electronics, it's my last chance at "redemption" for this course.

I like Serena

Neh, this is no fun for me. ;)

Ouabache

You did a nice job !! (!עבודה טובה)
There are typically several approaches to the same question.
Some take fewer steps than others.

Here is the method I was suggesting you try.
(It may help save you some time on an exam)

You found currents for the initial question to be I₁=1.105, I₂=5.211A and I₃= I₀ = 6.316A

Next was find V_AB and P_AB (with respect to R₁).

V= IR ; V_AB = I₁R₁ = (1.105)(4) = 4.42V
P = IV; P_AB = I₁V_AB = (1.105)(4.42) = 4.88W

Femme_physics

Duly noted Quabache

Next time I will certainly be wiser

I will try me hands on another exercise this morning (it's 4:30 AM here. I'm an early riser!)

Femme_physics

That was pretty easy. I didn't find P for each just for lack of patience. I know I know it!

I like Serena

Hmm, it seems you've been progressing.....

But wait! You did not get all the smurfs!
Which smurf did you miss?

Femme_physics

Yea I know finding the P in each of them...but com'on you just apply a formula it's soooooooooooooo easy! Lemme skip that pretty please?

Femme_physics

First question--

How come they get to pick for me the direction of I? Shouldn't I be the one determining it?

I like Serena

Not that. You made a mistake.
Perhaps I should have said that you dropped a smurf?

I like Serena

Well....

Look at the drawing in your first post in this thread.
You did not mark the directions of the currents (and as a consequence you made a mistake with it).
So I thought I'd better mark them for you!

(Just kidding, I just picked the first exercise that fitted your description. )

The real reason would be that the people who made the exercise would want the same answer from all students, so it's easier for them to check the answers. This means naming the currents and preselecting the directions.

Femme_physics

More like a typo! I've accidentally linked the wrong file

Femme_physics

Interesting. So you get different answers if you pick different direction for I? I didn't know that!

I like Serena

Yep! You found the smurf! :)

If you pick the direction of a force in mechanics in the other direction, don't you get a different answer too?