swansont

! Moderator Note This was posted in the politics section. Making all of this commentary off-topic.

Yes. The same is not true for acceleration. There are instruments that would be able to show that you underwent an acceleration, even if you could not look out into space for references to show that you had relative motion. Nobody else in the universe would detect this, as they did not undergo an acceleration.

! Moderator Note geordief You simply have to STOP HIJACKING THREADS If you have a question that is not directed at the OP, open a new thread to ask it. Link to the original thread, if needed. But it's against the rules to interrupt someone else's thread to talk about whatever is puzzling you The situation is exactly the opposite. Velocity is a vector, so any change in this vector is an acceleration. That's how it's used in physics, so circular motion is the result of an acceleration. It's the non-physicist who not only limits it to mean a change in speed, but distinguishes between speeding up and slowing down. Slowing down is an acceleration, too.

Perhaps no, but then, I made no claims about that. Can you show this mathematically? It's not obvious why this would be true. FE has no dependence on distance, and FC does not depend on the distance to the side of the cone. Seems to me if the distance to the cone could be made arbitrarily large and have no effect on the forces. Plus being the direction a negative charge would travel?

Yes. The observers are all in the same frame and measure the same thing. E and X are separated by 1 LH and the trip takes 1:15. Thus the measured speed is 0.8c They are in a moving frame, according to B. This falls under the relativity of simultaneity: Things that are simultaneous in one frame are not simultaneous in another. You should be able to figure out why: you synchronize clocks by sending a light signal back and forth between them. In B's frame, this light travel is not symmetric - when X sends out a signal, it takes a certain amount of time to reach E, but E is moving away from the light, so the light has to travel a greater distance than their separation. When E sends out the signal, it travels a shorter path, because X is moving toward the signal. In the earth frame, the path is symmetric and the clocks are synchronized. Clocks striking <whatever hour> will be measured as simultaneous in that frame. But not in B's frame, because of the relative motion.

No, not if it’s seawater, or of similar salinity ”Human kidneys can only make urine that is less salty than salt water. Therefore, to get rid of all the excess salt taken in by drinking seawater, you have to urinate more water than you drank. Eventually, you die of dehydration even as you become thirstier.” https://oceanservice.noaa.gov/facts/drinksw.html

The units would depend on the problem, and you have not provided enough information to answer. Other than it would be a unit of length.

B is moving essentially tangent to the observer. The radial velocity is zero. The tangential velocity is not.

Drink all the salt water you want to.

Then the units would be in the amplitude, A Not in the sin function, or its argument

The units come into these calculations through the differentials. If you integrate dx, for example, you can have units on the limits of the integration, if it’s appropriate for the problem. But it’s not proper if it involves a trig function.

I am aware, but none of that was brought up in this thread. You have to provide context. We can’t read your mind. So I ask again: to what object do you refer?

No, I simply referred you to the answer that’s been provided perhaps 20 times in this thread. I chose to answer in a way that referenced physics, to make it marginally harder for you to engage in denial. (and to forestall the followup of asking what the distance and time are)

! Moderator Note This is neither helpful nor on-topic ! Moderator Note And also this. Keep such observations to yourself. Also, if it wasn’t important, perhaps not mentioning it would be the best option, lest the discussion get sidetracked.

The sine function doesn’t give you that, so that’s not the way to calculate it What object? You asked about the trig function.

The observer is at rest wrt E and X, so it’s in the same frame. All of the measured values will be the same. In the FOR of B: E and X travel a distance of 0.6c It takes them 45 minutes (B is at rest in its frame)

! Moderator Note Then how about clarifying and narrowing the topic, so we aren’t all over the place.

Desalination cost is only part of the retail cost of water. This doesn’t rebut my post; I don’t see why I was quoted.

You have mutually exclusive requirements here - best intro book, but no textbooks. That’s not generally how science works. Non-textbooks are usually pop-science, where you learn about science, but aren’t necessarily learning much actual science. (i.e. you aren’t being prepared to go out and be a scientist, outside of the narrative of the book) I know of no entry-level pop-sci physics books, at least none marketed as such.

As is your original question, no?

No. It must be unitless as mathematic told you. If x is in cm, a must have units of 1/cm A sets the amplitude and also the units of the result, since sine returns a unitless value

B is not in the earth’s frame of reference. Do you understand what it means to be “in” a frame of reference? It means not in motion with respect to that frame. An animation can show objects that are in multiple frames of reference. (That’s one reason why it has to be animated) There are two objects shown in the earth’s frame: E and X. In that frame, the trip takes 1:15. There is no frame of reference where the trip is 1 LH and takes 45 minutes.

You haven’t shown the electric field. I assume it’s in the -x direction. The force on a charge will be the vector sum of FE and FC Ion drives do exist already

So the equation has to be Asin(ax) where a has units of 1/cm and A has units of cm

I think you’re right. Just that it won’t be cops. It’ll be bill collectors.