Recent content by razidan

Hi all, I've been following the launch of the first commercial lunar lander, SpaceIL. Because of its small size, there is not enough fuel for a more direct approach to the moon, so the path they are taking is multiple orbits around the Earth with impulses at the perigee, at each orbit. As I...

Oh boy... Thanks.

Homework Statement A pair of parallel conducting plates, each measuring 30 cm X 30 cm, are separated by a gap of 1.0 mm. How much work must you do against the electric forces to charge these plates with ##+1.0 \cdot 10^{-6} C ## and ##-1.0 \cdot 10^{-6} C##, respectively? Physics for Engineers...

here is how i think about this, and please tell me why it's wrong: the initial energy is zero. the energy the car has after it has reached the max velocity at some point x along the incline is ##E_{tot}=mgh+F_{drag}x+\frac{mv^2}{2} = mgxsin{\alpha}+F_{drag}x+\frac{mv^2}{2}##. This energy was...

Given that this is high school level, let's assume a constant acceleration. Is the power just the force times the average speed? The engine had to provide enough power against the forces as well as providing kinetic energy.

Sorry, i edited the question. the acceleration is from 0 to 28 m/s in 6 seconds.

I am tutoring a student, and this question was given to her. I believe it is not clearly stated and wanted your opinion. I hope this is the best forum for this. 1. Homework Statement What is the minimum wattage required to accelerate a car of mass m (don't remember the value) from 0 to 28 m/s...

Thanks!

I've never seen the formula written this way... Thanks, this was helpful.

Sorry , I wasn't very specific. t is the transmission coefficient, obtained from the full solution to the step potential problem. α=k is just a special caae (the problem has numerical values).

And when I did normalize the wavefunction with ##|c|^2## and I plugged in the values of ##\alpha=k## I got ##\frac{1}{\alpha}##

##<x>\int_0^\infty x|t|^2 e^{-2\alpha }##

The question was "find the mean distance an electron will travel into a step potential"

Thanks, but if I'm asked to find the mean position, isn't the rigorous way is to calculate <x>? And that's what I was trying to do.

Homework Statement I am trying to figure out the average penetration depth into a finite step potential, similar to this thread: https://www.physicsforums.com/threads/qm-barrier-penetration.104641/ But instead of just estimating the depth as ##\frac{1}{\kappa}##, i would like to calculate it...