Any idea how to work these problems

[Steven G]

I need to help someone with the problems below and am a bit lost. Please enlighten me.
I do understand what A/ angle symbol/ degree angle means.
Thank you!

 

[yoscar04]

Are they talking about a AC specific circuit? I recall there is a generalized Ohm's law for AC circuits: E=IZ, where Z is the impedance that depends on the particular circuit we are talking about, and all quantities are expressed in complex form. So, if I am not mistaken, we need to know the circuit in order to compute Z. From there we can obtain E.

 

[Deleted member 4993]

I need to help someone with the problems below and am a bit lost. Please enlighten me.
I do understand what A/ angle symbol/ degree angle means.
Thank you!
View attachment 20482

Treat those as pseudo vectors (in complex plane).

I_t = 1.4<75.4^o A \(\displaystyle \ \ \to \ \ \)I_t = 1.4 * [cos(75.4^o) + j * sin(75.4^o)] A\(\displaystyle \ \ \to \ \ \)I_t = 1.4 * \(\displaystyle e^{\left[j * \frac{75.4}{180}*\pi\right]} \) A

In electrical engineering (assuming problems are coming from there) the imaginary i (= \(\displaystyle \sqrt{-1}\)) is replaced with j. "i" is reserved as symbol for current.

 

[yoscar04]

Are they talking about a AC specific circuit? I recall there is a generalized Ohm's law for AC circuits: E=IZ, where Z is the impedance that depends on the particular circuit we are talking about, and all quantities are expressed in complex form. So, if I am not mistaken, we need to know the circuit in order to compute Z. From there we can obtain E.

The thing is to connect the E+ and E- to get the impedance Z. Do they say what are E+ and E-?
After talking to friends they told me that it looks like a transmission line.
I hope this will help you a bit. I apologize I can't provide more help. Maybe someone from the forum with a more electric engineering background can enlighten us more.

 

[Steven G]

Yes, I found out that this is from EE.

 

[Deleted member 4993]

Yes, I found out that this is from EE.

These are called phasors (as opposed to vectors, scalars or tensors). Please come back - showing your work - if you have more questions.