J.C.MacSwell

This is kinda relavent - You can see/hear the 'time delay' effect with sound rather than light in a thunder storm. If lightening strikes 3 miles a way you SEE it instantly (more or less) but there is a 3 second delay before you hear it crack as thunder. If it strikes 10 miles away then you get a 10 second gap. Similarly, as explained above, light from the sun takes about 8 second to reach us across the 93 million miles it travels.

More like 500 seconds.

valid point, lets say 1kw and 25000rpm

Even a light touch will put it through in that case...

...so you need the speed as well.

Also note that the force will not be directly in the line of travel and there will be a torque as well.

Can you do an experiment?

It wouldn't be a spiral, but it would be curved, and your hole would have to be dug such that it misses the center. (Assuming that it isn't dug from pole to pole)

The moon would still throw you off course.

Where does your iron piping lead to? Are you heating water in it? Where does the fan blow the warmed air to?

 

I would also recommend checking all door and window seals. Open your dishwasher and oven promptly after you use them to let that heat dissipate into the kitchen (dryer too). Change your furnace filters at least every month during winter. Reverse your ceiling fans so warm air is recirculated more efficiently. Buy an insulation wrap for your hot water heater if you don't already have one.

 

I know someone who used an old stand mirror in his back yard to bring sunshine to parts of his yard where the sun couldn't reach, and I wonder if you could do something like this to angle more sunlight into your windows. You'd have to make sure as the day progresses that you're not fading any furniture or pictures.

What's the rush? The heat will dissipate into the rest of the kitchen eventually.

Bernoulli's principle is not a law of physics like conservation of energy. Bernoulli's principle derives from conservation of energy assuming an inviscid fluid undergoing laminar flow at low Mach numbers.

 

The flow around an inverted wing is anything but inviscid or laminar. Conservation of energy does of course apply, but Bernoulli's principle is an improper expression of conservation of energy for inverted flight. In inverted flight, it is the bottom of the wing that does the bulk of work in diverting the airflow downward. Bernoulli's principle is approximately correct for normal subsonic flight when it is the upper surface of the wing that does most of the work in diverting the airflow downward.

 

Even for normal flight, Bernoulli's principle is to me but a hand wave: It begs the question as to why airflow is faster along the upper surface of the wing. By the time you get to a valid explanation for this effect (e.g., via the Coanda effect, the Kutta condition, onset of turbulence), you have already arrived at the fact that a wing diverts airflow downward.

I agree with what you are saying overall but generally it is when the wing is in stall that the lower part of the wing provides most of the lift. This is true whether the wing is inverted or not, and while a non symmetric airfoil will stall sooner when inverted there is no reason the top of the wing cannot provide the majority of the lift for inverted flight.

http://imagine.gsfc.nasa.gov/docs/science/know_l2/black_holes.html

 

With all respect, you aren't addressing the question. You are proposing instead that black holes are not the singularities they've been accepted as being. But you have no data for that. What we need is how Bojowald addresses the issue. If he doesn't, then that is a problem with his hypothesis.

 

If he simply stated that it wasn't a singularity, how would that change any of the observable or predictable aspects of a black hole?

Assuming equally symmetric riders of the same density the heavy guy wins. The drag coefficient is probably the same or very close and the volume of the riders is proportional to their weight.

The frontal area of the heavier guy is, however, proportionally less.

Advantage heavy guy!

So, most people think of rotation in 3D with respect to an axis, which is like rotating each 2D plane perpendicular to the axis. But relativity says we live in a 4D universe, although time is a rather special dimension.

 

Anyhow, I have several questions about rotation. What would each of the following look like?:

1. *Rotation in the real world. How is the time dimension affected?

2. *Rotation in 4 normal dimensions (called [math]R^4[/math]?)

3. *Rotation in spacetime, along the time axis.

4. *Rotation in spacetime, as if it were [math]R^4[/math]

 

I'm not really sure what I'm looking for, or even if there is anything to find. Maybe I'll have an idea when I see the answers...

1. No effect on the axis, but the further from the axis the more time slows down.

2. 3. 4. Hmmm...wonder if any of these resemble "quantum spin" in any way?

although I Did read an article last year in New Scientist stating that Cold temperatures Accelerate nuclear decay making the Half-life shorter.

 

however, Not being an Expert in this field, I cannot comment as to it`s Validity.

All other things being equal cold temperatures should speed the process up a slight but predictable amount, as per time dilation effects. (Two identical "twin" samples the warmer "twin" stays younger)

Someone always gets there before you

Don't feel bad. I'm heading back now to give your idea away to the person who will get the credit for it. Neither he nor I are original thinkers but we manage to pilfer lot's of ideas with our time machine (we stole the design for it also)

Behave like waves and hit like particle!

Float like a butterfly, sting like a bee!

I think he still wants the earth's atmosphere to be included. It seems to be more of a practical question. I think the temperature of space was like 2.7 K or something.

That's the idea. No atmosphere would amount to 2.7 K more or less depending on the direction.

I want to include the radiation component of the atmosphere (not any conduction / convection contribution) which should be greater than the contribution of the CMBR.

To get an intuitive sense of this, picture yourself as one of the asteroids, and your twin brother in the same orbit right beside you. If you reach over and grab him nothing much changes. You don't both go plummeting toward the sun.

OK - Clear sky then. Ground level summer in Botswanna compared to Winter in Northern Norway?

Nova Scotia, Canada, sea level, temperature at ground level 0 degrees Celsius, typical temperature gradient/distribution above that, say 75% (average for a clear night?) relative humidity, typical relative humidity distribution above that. Midnight on a typical night in early March

Anything else anyone could think of being typical values.

Botswana or anywhere else in other conditions would make interesting comparisons.

So what's in the kettle that makes it "suck" more electrons from the wall socket than the lamp? Is it the resistance of the heating element? If so why does the resistance of the heating element of the kettle make the wheel of the meter spin faster than the filament of the lamp bulb?

 

By the way, is the resistance of the heating element in the kettle greater or less than the filament in the bulb of the lamp?

The kettle resists less as YT said. This increases the flow of electricity.

I believe Einstein said "you cannot travel at the speed of light because if you did, you would instantly reach your destination.

 

but if the distance is 10 light years away ...even if you travelled at the speed of light you would not reach your destination instantly.

By your new reference frame the distance would contract to zero and the time lapse would be zero...thus instantaneous.

I'd guess it depends ALOT on the daytime average temp too... the best option I can give you is get a black body thermometer and pop outside Can anyone tell I'm an experimentalist?

Is their such a thing?

I don't actually know, but I do know that it's ALOT hotter than 2.7k because there is alot of reflected heat from the earth, that's why on cloudy nights it feels warmer, the clouds reflect more of the earths heat back to the surface...

Exactly. Reflect, absorb and re-radiate. Even when it appears clear this effect is still there but to a much less extent.

I'm basically looking for an equivalent temperature for a clear night at sea level. I know it would depend on the temperature and humidity which would vary all the way up through the atmosphere.

My experience (guess) is that a clear night vs overcast is worth at least 4 degrees Celsius in terms of freezing water. Not saying that is right, but that would indicate that the clear sky must be equivalent of well below freezing temperature in terms of a radiation heat sink.

From the earth's surface, on a clear night, what is the equivalent temperature of the night's sky?

I notice that (as I expected) water will freeze (shell) over in a bucket at +2 C when I am watering my rink at night. When it is overcast at night I wait until it is below freezing. I'm roughly at sea level.

Obviously the water is evaporation cooling and radiating more than it is receiving radiation and conduction in order to do this.

I know it is not as cold as 2.7 K because the clear atmosphere is "clear" in the visible range but not all of the rest.

So what is the equivalent black body temperature of the open sky?

I voted 1. 1 out of 100 seems ridiculously high to me (what percentage of Earth's "Amoeba Time" have we been listening?)

But I think there are a lot more "Amoeba Planets" than just 100.

10,000 seems very low to me. On the other hand 2.2% of them "listening" seems awfully high.

I think the point of the question is to look at the force in the direction of motion. I'm not sure if you'd consider the force on the rudder to be drag, if one were to assume that was restricting the lateral motion, since drag is a speed-dependent quantity and the speed in that direction is zero.

 

This is a physics 101 problem; one should try not to read too much into it.

By convention there would be lift forces perpendicular to the flow and drag forces in the direction of the flow.

How small of a scale or vector I guess can science currently detect the effects of or realities of relativity be it general or special?

Magnetism would be an effect of special, would it not?

Maxwell's equations didn't exist, and Michelson and Morely's experiment hadn't been done, so there really was nothing to prompt his relativity theories.

are they in solution or as solids?

 

if they are solids, nothing will happen if they contact, solutions wil form aluminium hydroxide and sodium sulphate.

 

nothing dangerous though the reaction is exothermic.

Thanks