Recent content by tsw99

If I have a constant emf, then connect it to a resistor and an inductor and capacitor in parallel. At the time when the switch is closed (I haven't drawn it), the voltage across L and across C should be the same since they are in parallel(?) (in fact it should be in any time later) But...

Yes, I understand what you say, but as I said when we derive the Pressure-depth relation, we consider the weight of the water to find out the pressure. But if we replace the water by an object with same mass, my question is, why we can say that the pressure exerted by the water is still the same?

But if we see the derivation of the first equation, we use the relation of the weight of the column of water (not other objects) equals to the net force arises from the water above and below. If the density of the object is greater than that of water, it will be sinking obviously, so the system...

As we know P=P_{0}+\rho gh If now I put an object of height h into the water, just completely submerged, why the pressure below the object not P=P_{0}+\rho_{obj}gh instead? Is it because it may not be in equilibrium or is it due to some other properties of fluid? Thanks!

Thanks for your suggested solution, but I completely do not understand how it works. Could you please elaborate on it? Using your method, I figure out the net EMF is 4V, but I do not understand "how much charge is going to move in the circuit", there should be none right? Because in fact it is...

Are you sure C2 and C3 are in series? Because they don't have same charges.

It is neither a homework nor coursework problem, but I really want to know the solution. Homework Statement 3 charged capacitors are connected as shown in the diagram. What will be their final charges, potential difference when equilibrium is reached? Units are arbitrary...

Linear momentum is conserved because of Newton's 3rd law. I think it is on every physics textbook 3 laws are essential, they are not proved from each other.

Yours is a probable answer. Does that mean the car is skidding up the incline? So the friction does not provide the force to travel upward? Frankly speaking, I never saw an electric toy car travels in this way. I believe it is a poorly set question.

Homework Statement I encountered this past exam paper question in Hong Kong when I was giving tutorial to a high school student. I am confused with the answer provided by the official authority. The question is (in exact wordings): Homework Equations The Attempt at a Solution The friction f...

Thanks, I understand what you mean, so which part do you suggest to trim a bit for a first email to professor? Expressing interest on his research or my background information? oh I'm sorry I don't quite get the meaning of your last sentence.

Really? That's a real challenge, so I need to trim it to a few lines, but still expressing the same level of interest...now I have 8 lines and a CV attached

Yes, I am going to skim through his papers, introduction, abstract and summary, and perhaps some of the details. Thanks for the advice.

Thanks for your idea, I think that is very useful. Hope that he will give positive response

Thanks for your advice, but would you suggest I should propose a meeting with the professor first (then discuss and ask question if he is willing to), or to ask questions in the first email?