Recent content by brasilr9

I think I figure it out. Since it's speed is constant, there's is no change in tangential velocity, hence tangential acceleration remain zero.

A particle is moving in a elliptical orbit with uniform speed. How can I tell whether there are tangential and normal acceleration or not on the particle? (At A B and C ) thanks for help!

The net charge of the whole circuit seems to be zero. So I'm not sure that whether you can you use it or not. But I don't have any idea either.

I get it. thanks a lot!

So it is possible to solve this problem if the electron cloud is a spherical ball which charges are uniformly distributed inside it?

Well... I agree with you.

Is the shell theory(a charge in a hollow and charge uniformly distrubuted sphere experiences no force due to the sphere) based on that the test charge won't change the charge distribition of the sphere? If it is, in this case, the charge of electron cloud sphere won't distributed uniformly...

Sorry, I frogot to translate a important information of the problem. The problem said:There's a spherical electron cloud 10Å from the centre, charged -e, and charge is uniformly distributed on the spherical shell. Sorry for making mistake.

If the proton is out fo the sphere, of course we can see the electron cloud as a point at the sphere's center. But the point is, even we put the atom into a electric field, the proton doesn't run out of the electron cloud, it just shifts, so the proton and the center of the electron cloud sphere...

If the electron sphere is uniform, the forceinside the sphere is zero. Just like the graviational force inside a hollow planet is zero. So how we use \frac{q_1 q_2}{4\pi\epsilon_0 r^2} ?

The force on proton due to field is F_p=eE_0 and force on electrons due to field is F_e=eE_0 These two force tends to pull proton and electrons apart. And I think the force between them try to pull them together, which is the force I don't know how to deal with.

I have some problems. If we put the atom into the field and the electrons still distributed uniformely, how we calculate the force between electrons cloud and proton? If the proton is inside the spherical, isn't the force between them be zero? And if electron cloud been distorted, it seems more...

Assume there's a hydrogen atom. Its proton(charge +e) is at the center of a spherical electron cloud(-e) which radius is 10Å and the electrons are uniformly distributed at the sphere's surface. If we now put it into a uniform electric field E_0, what is the distance \delta between the proton...

The frequency of the emitted sound from the source.

If a sound source flying at a speed faster than a sound, it will produce a Mach cone and shockwave, like the figure. But what will happen if the frequency changes continuously during the flight? thanks for help!