Hipparchus made the first stab at being able to predict the locations of the planets, moon and sun in 250 BCE, using the obsevation data from the Babylonians and Sumerians. Not too shabby a stab, either, because with the exception of some of the do-si-does that happen in retrograde motion, it...
If the plate is rigid, the force of the rod would be totally transferred to the plate; the pressure would be distributed evenly.
Yes, every part of the plate would exert 50 pounds of force. A balancing force might be concentrated at any point on the plate, or distributed over the whole plate.
Underground coal fires are a worldwide fact of life. I believe there are over 50 known big ones, the biggest in China. Colorado had (has?) one a couple of years ago when a forest file (was it the fatal Thermoking fire?) lit it.
But...
On the average worldwide, an acre-foot of soil...
Some proportion of "sea ice" is actually glacial ice that has spread from the land to float on the sea, called shelf ice; it is the primary source of icebergs, for example. It was originally snowfall inland.
Ummmm, yes. But when the outer shells of the red giant are sloughed off, the mass of the star declines (by, perhaps, 80-90%?) and that changes the dynamics of the planets. Likely they will slow down and move to orbits farther out. Once the white dwarf is formed, its gravity is too high to...
The acceleration due to gravity is about 9.8 m/s/s at all times and everywhere within a shell of space surrounding the sphere defined as "sea level" on Earth. Below that sphere it declines to zero (linearly? - not sure) down to the center of the Earth; above that it also declines, but...
To quote Richard Rhodes in his "Twilight of the Bombs" (Chapter 16):
"In 1986, when I helped the Nobel Laureate Louis W. Alvarez write his memoirs, Alvarez commented one day on the importance of keeping track of highly enriched uranium. Speaking of a quantity sufficient to form a critical...
Yes. They're called Planck length and Planck time. The Planck length is 1.61619926 × 10-35 meters, Planck time is the time it takes light to cross a Planck length.
From wiki:
"Simple dimensional analysis shows that the measurement of the position of physical objects with precision to the...
Matter flew out alright, but the thing that exceeded the speed of light was the expansion of space itself. That expansion doesn't (even today) require the actual movement of matter, though it appears to us that that's the case. The expansion of space can cause things embedded in it to appear to...
Well, actually I managed to find the answer. For those who are interested...
Part of the question was incorrectly stated. I said all the epicycles have a common period and phase (they all point the same way). That's true only for the epicycles of the superior planets (Mars, Jupiter, Saturn)...
Perhaps you are seeing something being confused with SSB (single side-band) signalling, though that is a kind of FM rather than AM. No, the signals you get from the air must have a zero DC component, which means they are symmetrical, and rectification (what used to be called "detection") is...
Pretty generally the spec on the motor will be "xyz amps at abc rpm". At very near zero rpm, it will try to drain a lot more than that. Motors quite often will accept 10 or more times their ratings under those condition, and batteries can supply it, for a short time. Power supplies often...
With respect to the freezer, yes, it is not a closed system. If it were, then it would not be able to freeze (separating heat from not-heat requires work). How ever, since you know that that is true, then you also know that everything that enables that work to get done has to come in through...
In the early 60s, before the PTBT went into effect, the Soviets did a number of such tests; they were wild about throwing their primitive missiles of the time up in trajectories of thousands of miles across their own territory, ending in nuclear blasts above Kazakhstan and Novaya Zemlya. The...