Recent content by sporkstorms

Whoops. I was like a sheep, following right over the edge of a cliff.

And after you recall Newton's first law, be sure to draw a force diagram before solving the problem. This will help ensure that you get the signs correct (arrows pointing in opposite directions will have opposite signs).

One of the main points physicsprasanna is implicitly making, is that velocity takes into account the direction. Speed does not.

Break the problem into two parts. Calculate t1, the time it takes the stone to fall from her hand to the bottom of the well. Then find t2, the time it takes the sound to travel from the bottom of the well to the top. The total time is just t1 + t2.

I think you're misunderstanding the purpose of these forums. If you truly want to learn the material, forget the homework deadline. You already dug your own grave anyway, by waiting until the last half hour (not that I'm condemning this - we've all been there). Instead, work out what you...

Keep in mind the physical significance of the answer you got for part a. You say it's negative, which means you set up your axis pointing from the sky down to the ground. If that's not the case, you should re-evaluate how you did it. For the sake of completeness and so we can see the whole...

ek, another way to think about this is this: Because the particle is confined to an infinite potential well, it must be in that box between 0 and L. It cannot escape because the potential barrier at x=0 and x=L is infinite. So translating that into math, the probability of finding the particle...

In case this is where your confusion lies: n is just a quantum index. Specifically, it's an index of energy. As you will learn if you study QM, the energy of this system is quantized. This means you cannot have any arbitrary energy. Instead, only certain discreet values are allowed...

Don't get me wrong, I'm wasn't trying to say that was a better or easier way.. just another way. Personally, I hate trying to remember equations. I just naturally remember the ones I've used often enough, and only make a point to memorize ones that are general and used to derive the more...

Yea, sorry.. If you want to be pedantic, in MKS you need that. (To be even more pedantic though, my expression is perfectly valid in cgs ;) But either way it illustrates the point that r and p are orthogonal, resulting in a zero electric potential.

Well, another way to look it at is this: When you calculate the dipole moment, you find it to be in the x direction. r (pointing to your observation point) is in the y direction. The electric potential of a dipole moment is: \frac{\vec{p}\cdot\vec{r}}{r^3} and \vec{p}\cdot\vec{r}\ goes\ as\...

I laughed so hard the first time I saw a commercial for one of those... I think it was the first, and only time I'll ever see Maxwell's equations on my tv screen. Truly absurd. :biggrin:

The first step in a problem like this is always: draw a diagram (done), and label all the forces with vectors [arrows]. So label the forces first (tensions on strings, forces of gravity, etc). Then, we know the system is in equilibrium, which means the net force is zero. That is, all the...

You don't have to solve it, or even start solving it. Just explain some thoughts you have on it, or tell us what you know, or what you don't know, or what you feel needs clarification, or ... Basically show that you've at least tried to read the relevant material in your textbook, and put a...

"E = -E0j" and "-qEoj/m" sound like something you picked up from an example problem. That is definitely not the general expression for an electric field or acceleration of a particle in a field. E is an arbitrary vector. It can be just about anything. When they ask for the magnitude, this...