# Search results

1. ### Mechanical advantage machines

I've been at this problem for a good hour now and I just can't figure it out :bugeye: Please help me think through this! It is a very difficult problem in my opinion. Or maybe I'm just missing a fundamental point...Thanks in advance...
2. ### RC Circuits, capacitor charges and voltages

0_o I've taken both physics I and II in college and I'm brushing up for the MCAT. I most definitely never came across either theorems :X THank you for all of your insight! It help tremendously! :)
3. ### RC Circuits, capacitor charges and voltages

BvU: that was an amazing explanation! ....Why can't textbooks just put it that simply! I wish I could transplant y'all's brains into my head for this test. Yikes! :)
4. ### RC Circuits, capacitor charges and voltages

Ok I think I got...so when they're in series maximum charge q = emf x C but when you have resistors in parallel with the capacitor, it's another story?
5. ### RC Circuits, capacitor charges and voltages

Whoops sorry about that! I was trying to make it easier for you to understand haha. Ok...sooooo basically, question 24 is just an awful question? And so, when a current comes across a resistor before reaching the capacitor, that resistor will zap some of the voltage that would otherwise get...
6. ### RC Circuits, capacitor charges and voltages

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7. ### RC Circuits, capacitor charges and voltages

BvU hi. that still doesn't explain problem 24 though. Problem 24 is answer C. The answer provided states "there is no dependence on resistance of any kind".
8. ### RC Circuits, capacitor charges and voltages

Ok I have edited my question, hopefully this explains it better. I am still so confused.
9. ### RC Circuits, capacitor charges and voltages

No - questions 23 and 24 are stand alone questions and neither has a figure provided. I will edit this post again with my thoughts and further clarification of why I am confused, please check again gneill in a few minutes. Thanks so much.
10. ### RC Circuits, capacitor charges and voltages

These are 2 stand alone problems, however the answers disagree with one another and I am trying to reconcile their differences. Any insight would be appreciated! :) The answer is C. The answer provided with this question is that "there is no dependence on resistance of any kind". However the...
11. ### Conducting bar on a rail question

qvB = IxB? Where x is distance?
12. ### Conducting bar on a rail question

I took physics a while back and am only just refreshing before the MCAT. I remember the equation F = Eq + qvB.
13. ### Conducting bar on a rail question

This problem is way over my head. :/ *white flag* I surrender. Hopefully it doesn't come up on the MCAT!
14. ### Conducting bar on a rail question

The passage says it definitely does climb it, but gives no explanation as to why. I think they assume I should know :/ lol
15. ### Conducting bar on a rail question

I say that because my textbook says that this is the only reason we use rotating coils in real life, because having infinitely long rails to produce current is impractical.
16. ### Conducting bar on a rail question

Also to .Scott: wouldn't the current stop when the bar reaches the end of the rails?
17. ### Conducting bar on a rail question

Right, the current is changing as .Scott said. Since there is current due to voltage, this would mean that there is a second magnetic field created right? And say this current created a magnetic field that opposed the external magnetic field. Would this be the reason the bar rises? I mean, if...
18. ### Conducting bar on a rail question

Disclaimer: this question is really just for my own edification in preparation for a test. In the figure above, we have a conducting bar that is placed onto two sloped conducting rails. The box labeled V is a voltage source. Lastly there is a magnetic field starting from the "base", rising up...
19. ### Conducting bar in a uniform magnetic field

Thank you for clearing that up! It all makes so much sense now! :)
20. ### Conducting bar in a uniform magnetic field

Thank you tsny !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :)))))))))))))))))))))))))))
21. ### Conducting bar in a uniform magnetic field

is it as simple as i think it is? the current goes from bottom to the top of the bar...so as Tsny said current is the same as velocity. SO using the right hand rule it's pushed left?? Is that all there is to it? Then I don't see how Andrew Mason's explanation fit in. The current in the rod adds...
22. ### Conducting bar in a uniform magnetic field

Yes I understand that, but I don't see how that relates how the bar is moved right or left
23. ### Conducting bar in a uniform magnetic field

Mr. Andrew Mason and Tsny, could you please let me know if my thoughts are correct? They are as follows: The external magnetic field is pointing INTO The plane of the computer screen and the velocity of the bar is from left to right. Using right hand rule, the positive charge moves to the top...
24. ### Conducting bar in a uniform magnetic field

DOHHH ! I think I get it! Please hold on and let me reformulate my question so that I can ask you to see if I am correct!
25. ### Conducting bar in a uniform magnetic field

Hello Tsny thank you for your reply. Yes I am familiar with it. Thumb is velocity, fingers are the B field, and palm shows you the direction of force on a positive charge.
26. ### Conducting bar in a uniform magnetic field

Dope! I still don't get it!!!! I followed you up until a certain point. I understood that the B field goes into the paper on the right side and comes out from the paper on the left side and that it adds to the field on the right and reduces the left BUT how did you make the connection that it...
27. ### Conducting bar in a uniform magnetic field

I'm studying for the MCAT and this problem came up. The correct answer is D. However the explanation was very confusing. The explanation is verbatim: " Let's start by considering A. Using the right-hand rule on a current running through the wire in figure 2 shows you that the rod is pushed...
28. ### Capillary action

How is B more correct than D? Both show that forces between glass and fluid are stronger than those between fluid molecules. Thank you for any insight!
29. ### Ideal fluids, bernouilli's law

Thank you both the disvussion was very helpful!!!!
30. ### Ideal fluids, bernouilli's law

Thank u for your reply :) but how come we can assume that force is equal at points A @nd B?