Recent content by Alex Schaller

If an electric charge q is moving with a certain velocity v and we want to slow it down, this can only be done with an electrical force because magnetic force is perpendicular to displacement, correct? (watch video, time stamp 0:42) video

P arrangement: The force F acts along the string that links both springs. So, there would be a force F acting on Spring 1, and the same force acting on Spring 2. Therefore, both springs would be elongated the same distance x, as just one spring would be elongated if a force F is applied to the...

A picture is worth a thousand words... Would you sketch such a picture?

You can check at the gizmo's details in the following link: https://photos.app.goo.gl/3ysat3fdC6MxHqPf6 It draws energy from the mains, so it would not be a perpetual motion machine.

I think that work would be different for both sides.

If so, would it be proper to replace ## \vec dr \ ## by ## dr . \hat r\ ## so as to perform the scalar (dot) product of the integral? (@Vanadium 50 is welcome to answer, although this is more like a math scheme instead of a physics intrigue).

Provided the air gap breaks down at approx 30 kV/cm (which is a magnitude of Electric Field) as you mentioned, couldn't we derive from there the voltage as: ##V=-\int \vec E\cdot\vec dr## substituting ## \vec E ~by~ 3000000~ \hat r~ \frac V m##?

It is true that a capacitor needs two ends; a sphere can also be considered a capacitor, where the other end are the walls of the room that encircle the sphere. Everybody knows that a perpetual motion machine cannot be built (as per the second law of thermodynamics).

A big sphere means it can hold a greater capacitance (and therefore a greater charge, as capacitance is the charge per unit voltage). Could we say this is correct?

The greater the capacitance, the more charge the sphere can hold. The more charge it holds, the greater the electric field it produces. The greater the electric field, the longer the spark. Does this make any sense?

Do you agree, so far?

So I think that, in order to hold a voltage of 210,000 V, its original charge should be something around 525 nC.

I also know that the sphere's diameter is 30cm. So, its capacitance should be 2.5 pF.

Provided the length of the arc of an electrostatic generator is 7 cm, can we state that its voltage is around 210,000 V? (details as per link below) https://photos.app.goo.gl/MKSpviQwPh9eS5jZ7

Indefinite integrals can be regarded as a set (family) of curves, and each of the curves can be obtained by shifting in a parallel the curve, upwards or downwards (along the "Y" axis).