swansont

This is a long-standing issue of definitions. Using the normally-used definition of mass (the invariant mass or so-called rest mass) this isn't true. It holds if you use a certain definition called the relativistic mass, but that causes other difficulties. What is true with either definition is that the kinetic energy's dependence on mass diverges at c, and then we reach the conclusion of it requiring infinite energy to do so.

I assume Deity status is a rep power of 25?

I think it's more accurate to say that there is a gradient in the frequencies — the rate at which time passes is different depending on your position. I don't know what "bent in time" means or how to interpret it. The time dilation is a kinematic effect. Once you stop spinning, every point on the propeller is in the same inertial frame, and the time dilation effect goes away.

Hydrogen masers, cesium clocks and rubidium clocks all exhibit the same time dilation effects. This would seem to rule that conjecture out.

Is it possible for you to exert a force on an object without it exerting a force on you? If yes, give an example. If no, then you must at least provisionally agree that forces come in pairs. An example of the law, not the law itself. F=ke*Q1*Q2/r^2 describes the force on Q1 and Q2. You cannot have a force on Q1 without having the force on Q2. One charge does not exert or feel a force of there are no other charges around.

That assumes you are right. If the rest of the internet is right, the amount of misconception goes down. Merged post follows: Consecutive posts merged Oh, my. Is ego bosonic?

Indeed. One needs to measure the amount of rotation to see the magnitude of the effect, but since we're all rotating like this it would only come into play for someone with different orbital parameters. Locally, assuming linear motion won't have much effect, and then we can assume we are at rest. The expansion is an effect of General Relativity, and basically means that distant objects are in a different frame of reference than our own, and I think I'm right in saying that these are not simply different inertial frames. The space is expanding, (though calling it an ether can be problematic because of historical reasons) Locally, you have inertial frames and nothing exceeds c. But the remote frame is non-inertial, as viewed by us, and you lose the restriction on c unless you account for the expansion of space. Or perhaps it's better to say that with regard to reference frames, the expansion of space is a non-inertial effect. (If Martin happens along he may find some fault with my generalizations. Much of GR is outside my area of expertise)

emphasis added — I've highlighted the relevant part of the quote. Inertia can be equated to the body's inertial mass. It's not a force. It's the mass. The employee could have said that there are 1000 grams in a kilogram as part of that video. It would be true, and yet not be an explanation of the 3rd law. The third law is decidedly NOT only a consequence of the inverse-square law. You can observe it in e.g. a spring between two masses that are held together and then released (a simple explosion). That force is linear in x. (Edit: I see D H mentions the example of Hooke's law as well)

You wouldn't. But science doesn't like ad-hoc-iness; if you can't test it, why bother assuming it? In whose frame? That needs to be specified. In the mass's frame, no. In the observer's frame, yes, because of length contraction.

The satellites experience a centripetal acceleration, because they are in a rotating frame. Even though the speed stays the same the velocity changes (direction of motion) so it's still an accelerating frame. 1. You can deal with accelerations in SR; you can take the time dilation equation and use the instantaneous speed at any time t, which you know from your acceleration, and integrate to get the accrued time dilation. (You are essentially creating an infinite number of inertial frames using this method) 2. Yes, if the trips are identical. 3. The breaking of the symmetry does all happen during the acceleration. But it's also independent of the amount of acceleration (i.e. the turnaround can be instantaneous or slow, and that won't affect the basic answer — the amount of dilation depends on v and the length of the trip) 4. Yes. This is quite similar to earth and satellites. 5. No. Constant velocity means no acceleration.

I don't know if it will make them like math, but it shows that math has applicability. But the problem is that the math in the show isn't really accessible to them — they never really show the math, only the analogy of why it applies. But they do teach rigor and skepticism, to some extent, which is good. That's something that could be discussed in a class. If there were a way to tie this in with simpler problems that the students could actually solve for themselves, I think it would be more useful.

How do you measure how much misinterpretation is going on? Given some of your statements (e.g. the misrepresentation of the third law here and in another thread), I submit that you are not the best arbiter of such an assessment.

If it's a statement about the 3rd law, yes. Sisyphus has already explained why it is wrong. The statement itself is true, but the quote didn't say it was explaining the third law. You did. I'd like to confirm who is misinterpreting the third law. Inertia is not a force. If I exert a net force on an object it will accelerate. If the object has a large mass, the acceleration will be small. Merged post follows: Consecutive posts merged r is the separation distance between the two masses

That would be problematic in regard to the postulates of relativity — the laws of physics are the same in all frames and there is no preferred frame. If the constants depended on the frame, you could tell what your speed was with respect to some arbitrary frame, without measuring anything in that particular frame. And then there's the effect this would have on c.

it is said is a rather nebulous attribution, and you've been asked to give a more specific reference for the assertion. It is implied that this is standard cosmology/cosmogeny. You need to support this claim.

The objection I have to that is that it ignores the historical view, and appears to assume that the galilean/Newtonian view is obvious. But if it were so obvious, why did the Aristotalean view persist for 2000 years? And the OP did not ask if "tend" should be there, rather it asked why it was there. All the rest is, I think, semantics and opinion. Is there a quantifiable way to show that one statement is better than another?

That's a claim, but it needs to be tested. We know that motion and changes in gravitational potential will affect time measurements in predictable and verifiable ways. How do you propose to test your hypothesis?

In SR inertial frames have no acceleration, i.e. Newton's laws describe the motion of the object. Any objects moving with respect to each other are in different inertial frames. We typically ignore gravity in looking at the twins paradox, so that the only acceleration is the twin that has to turn around to return to earth. That changes the inertial frame of the twin. In general relativity one finds that an object falling freely in a gravitational field is also in an inertial frame. A propeller is not in an inertial frame because it is accelerating, owing to the rotation. The earth and satellites are not in inertial frames, again owing to rotation. However, we "fake" an inertial frame (much like we do when we refer to the Coriolis force, which is an artifact of the rotating earth and our desire to treat the earth as an inertial frame). To an observer away from (and not rotating with) the earth, if one moves east at some speed, one is really moving faster than if one moves west at that same speed, so when using the earth's frame we add a Sagnac term, adding or subtracting time based on the motion in the east/west direction. One complete E/W circumnavigation will add or subtract 207 ns. Once we account for the Sagnac effect, our reference frame looks like an inertial frame, at some gravitational potential. Clocks in orbit are moving relative to the earth (unless geostationary) and have a different gravitational potential, so both of these effects must be accounted for when comparing them to earth clocks.

That quote is not found in that link. Where does it come from? I don't trust ellipses. Merged post follows: Consecutive posts merged Case 1 is about action/reaction force pairs, and this does not deal with unbalanced forces causing an item to move. Case 2: If the object is free to move, then any force at all will cause an acceleration, proportional to the mass. The limiting case is zero acceleration for zero force, ergo, there is no such thing as a resisting force. You appear to be assuming that friction is a natural circumstance rather than an external force which must be accounted for separately.

Actually my objection is to your shortening of the statement. And there is no circular motion at constant velocity, by definition — velocity is a vector. —— From wikipedia, (and quoted by insane_alien above) the first law is: Lex I: Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus impressis cogitur statum illum mutare. Every body perseveres in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed. i.e. "uniform motion" is defined, and not ambiguous http://en.wikipedia.org/wiki/Newton's_laws_of_motion#Newton.27s_first_law:_law_of_inertia ——— In regard to the OP, I suspect the word "tend" may have some ties to the notion that Newton displaced, which was that an object's natural tendency was to come to rest, i.e. that was a dynamic thing. Moving objects tend to come to rest. The translation of Newton is saying that no, it's only objects already at rest that tend to remain that way, and they do not start to move on their own, i.e. there is no tendency for spontaneous motion: motion from a state of rest requires a force.

But in that sense, they act on different objects. The motion of an object is the result of forces acting ON it, as has already been discussed.

I guess it's a good thing that I never said kinetic energy causes it, then. I said, "You can have time dilation due to purely kinetic effects, as in special relativity." kinetic = relating to or resulting from relative motion. No mention of energy.

The problem with this approach is that it's all too common in "alternative" science discussion: find an area where there are still unanswered questions, and proclaim "my thesis explains this!" But your thesis has to be tested to be considered science, and you have to test it in experiments that can actually be done. It also needs to be consistent with science that has already been done. Your approach also suffers from the "search the internet until I find someone who sounds like they are agreeing with me" issue, which is a form of appeal to popularity, albeit using an odd definition of "popular."

A single frequency is a sine wave of infinite extent. You can't create this — you have a wavetrain of finite extent, which necessarily includes a range of frequencies, even if that range is small. In terms of the HUP, any transition has a finite lifetime, meaning that it has an energy width, from [math]\Delta E \Delta t > \hbar/2[/math] This is why clock people and metrologists (i.e. the people I hang out with at conferences) like long-lived transitions, because they are narrow and allow precise measurements.

Time dilation due to gravity is not dependent on the strength of gravity (g), it's dependent on the gravitational potential. You can have different gravitational potentials with the same value of g, and you can have different values of g that have the same gravitational potential. You can have time dilation due to purely kinetic effects, as in special relativity.