haruspex's latest activity

This is what I am missing. How does that follow?

But I don’t see a valid argument for that in the concentric sphere model. A single infinite charged plate clearly exerts a field on...

It might help to treat the mouth in more detail. Say it is a smooth quadrant of radius ##r##. We are interested in the limit as...

Ok, good. But I do wonder what happens if it's an extensible string. Such cases can be confusing.

Indeed, a standard example being the charge a point charge induces on a grounded sphere.

Doesn’t that result in the solution in post #11? But I am uncomfortable with this question. Infinite plates and potentials is an...

You may have misunderstood what @TSny was asking, which was to write an expression for ##dt## in terms of ##dK##. And you have that, in...

If a rod spins about its midpoint, each end is accelerating towards the centre.

I see no reason to doubt @BelieverOf143___ understands that. If the vector product rule can be used to prove the law of sines then...

I do not see how it was clear that the last equation in post #52 was wrong without doing the simplification. Maybe you are better at...

When given a task like this, you have to start with the definitions you are expected to work from. State the law of sines and the...

Obviously you had done those steps, so I expect you to post where you actually got to, not several equations back, making me redundantly...

Well, obviously, the usual steps of cancelling out the non-infinitesimal terms and discarding the second order infinitesimals. What...

I alluded to that in post #44, but I think it is ok because we can instead view it in terms a tension transmitted around the curve and...

But that element is the "exhaust". The loss of it is removing momentum from the system. It is the water leaking from the cart.