Recent content by LuigiAM

Thanks for the help! It's still not intuitive for me though. I'm going to try to read through this stuff again. It feels like this is something I need to understand.

Hmm... it says the motor has a voltage drop Vmotor which appears to be equal to the emf. They the resistance in the armature ra produces a voltage drop Va = Ira. This looks a lot like the emf equation I'm used to. But then they say the back emf is produced by a rotating armature? I'm not sure...

Ok thanks I'll print this out and see if I can work through it

I googled it but what I found was talking about Lenz's law... is that the right thing? We kind of skipped Lenz's law, except for the equation Ei = (-1) I / t where Ei is the electric field induced by a current. If I understand your example, the back emf would be the second resistor that is in...

Hi, thanks for your response. I'm not sure I understand the difference. I searched but I haven't found any reference to the words "back emf" in the course material. I was a bit surprised by the word "motor" because it doesn't show up anywhere in any of the assignments until now nor in the course...

Homework Statement A motor as an internal resistance of 0.5 ohms. It draws 20 amperes at full load from a 120-V supply. a) What is the emf of the motor? b) What is the load resistance? Homework Equations Potential difference between the terminals = emf - Ir (r = internal resistance) (P.D...

No, it's a paper homework and we're expected to submit answers on paper. I like that better honestly. Thanks for reminding me about including the units! I often forget to include them in my answers

Thanks for the reply. I think I'm just going to try the safe side and give the answer in terms of I but add a that if there is no current then there is no torque?

Homework Statement [/B] A rectangular wire of length 3 cm and width 2 cm is suspended vertically between two poles producing a uniform field of 2 T. Calculate the maximum torque acting on the wire.Homework Equations Torque = AIB sin(Θ) Maximum torque is when sin(Θ) = 1, so Maximum Torque = AIB...

Thanks for the replies. Yes, I re-copied the question word for word. Anyway I think the difficulty with this class is the language barrier. Our professor has a PhD in physics and worked as a theoretical physicist so he obviously knows the material. The problem is that his english is very poor...

Homework solutions were just posted this morning. The correct answer was "The electron volt is the energy acquired by an electron in moving through a potential difference of one volt." I should've suspected that this is what he was asking for because it's the definition he gave us in class. I...

Hmm I'm glad I'm not the only one who doesn't get it. I'm going to try to email the teacher and ask him if there was a mistake in the question. It doesn't seem to be related to another question since the question before it is about equivalent resistance in a circuit and the one after is about...

Homework Statement How much kinetic energy is in electron volts? Homework Equations Kinetic energy = 1/2 mv2 1 electron volt = 1.6 x 10-19 J The Attempt at a Solution [/B] It's a bit unclear to me what the question is asking, since no context at all is given. It's one of the questions in...

I guess it depends from what point of view you see things. Obviously there's always a way to get through a class even if the material and teaching is sub-par. No question about that. At the same time though, bad teaching does exist (though perhaps not as often as some students may claim) and...

Agreed lol. On my end I think I'm just going to hire a tutor for the rest of the semester.