Recent content by Dopplershift

Hello, I am currently a high school physics teacher in Chicago. I am thinking about going back to school to get a PHD in Physics. I currently have a B.S. in Applied Physics and a secondary education license. I would like to find a way to go back and get a PHD. I cannot afford to quit my job...

So, I am doing my undergraduate research project in Quantum Cryptography, and I have some confusion in a few areas, especially in the topic of continuous variable quantum key distribution. From what I understand, Discrete Variable - Single photon. That is, for example, the BB84 protocol. Bob...

Thank you!

I'm confused, how is the initial velocity zero? It says that the fuel gives us a v0 of 3.0*105? The problem is when I plug in the values of the conditions into my final equation, (equation 2).

The problem states: Typical chemical fuels yield exhaust speeds of the order of 103 m/s. Let us imagine we had a fuel that gives v0 = 3 × 105 m/s. What initial mass of fuel would the rocket need in order to attain a final velocity of 0.1c for a final mass of 1 ton? I derived the equation in the...

That makes sense. Thank you! :)

You didn't misunderstood, I mistyped, my apologies. It is dZ. My limits I assumed are 0<y<1 0<x< y

How to I integrate if the integral is a sum such as dz = y dx + (x+2y)dy ? And are my limits of integration correct?

Homework Statement Suppose you have a Triangle with the vertices, (0,0) (1,1) and (0,1). Integrating along that path. I have some differential function dZ where Z = Z(x,y) Homework EquationsThe Attempt at a Solution [/B] If I need to integrate, then I need to find the limits of...

Thank you, very much! :)

So would it be: \begin{equation} \begin{split} f(r) = rcos(\theta) \\ \frac{\partial f}{\partial r} = cos\theta \\ \frac{\partial f}{\partial \theta} = - rsin \theta \\ \frac{\partial f}{\partial \phi} = 0 \end{split} \end{equation} So the gradient is \begin{equation} cos\theta \ \hat{r} +...

if you're asking if I know how to take partial derivatives, then yes. The issue lies in I don't know where to begin since there is ##\hat{r}##, ##\hat{\theta}##, ##\hat{\phi}## in the equation.

Homework Statement Find te gradient of the following function f(r) = rcos(##\theta##) in spherical coordinates. Homework Equations \begin{equation} \nabla f = \frac{\partial f}{\partial r} \hat{r} + (\frac{1}{r}) \frac{\partial f}{\partial \theta} \hat{\theta} + \frac{1}{rsin\theta}...

Never Mind, I figured it out. I was overthinking the problem. Thanks for your help! :)

Okay, so I can setup the integral. \begin{equation} \int_v (r^2 - 2\vec{r} \cdot \vec{r}') \delta_x(x-x_0) \delta_y (y-y_0) \delta_z (z-z_0) dx dy dz \end{equation} I guess I'm confused how I plug ##\vec{r}'## into f(##\vec{r}##)