It is said that if a (non-frontal) collision with another car appears imminent and unavoidable, then the wisest course of action is to "put the petal to the metal" for maximum speed. The myth mostly concerns collisions at intersections typically at angles of 90 degrees.
The idea is that while the increased speed does in fact cause more damage, it also increases your inertia (resistance to a change in velocity) and thus yields the smallest accelerations and decelerations from an impact with a car of a constant mass and velocity. As we all know, survivability is a strong factor of acceleration/deceleration.
Would you test this myth to determine if faster collision speeds in non-frontal collisions with automobiles are actually safer for those in the faster car? It is obviously more dangerous for those people in the slower car, but then again, the myth only concerns the safety of the occupants of the primary vehicle.
Momentum (p = m*v) is a function of velocity too, but faster speeds may not mean more collisions, because the path will be less prone to deflection. The scenario of most interest is that you are traveling through an intersection and you see a car coming at you from the side (perhaps running a red light) like from a side street at an intersection (seemingly out of nowhere).
This happened to me once when a car (facing me and in the intersection) made a left turn on my green and hit the driver's door. Stopped him cold and spun his car 90 degrees counter-clockwise, but my car (about 45 mph) hardly deflected at all and I retained complete control as I braked to a full stop. I think that this myth might be true. In general, the fast you are going the better it is for you.
BTW, on the damage from the kinetic energy, your car will absorb the damage and spread it out over a larger area with higher speeds. Additionally, with more momentum, there is less deceleration, thus the faster vehicle incurs a smaller change in velocity. It thus absorbs less kinetic energy damage than it might otherwise be expected to absorb in any given high speed collision (assuming no collisions with immovable objects or flights off of very high cliffs, etc.).
Tuesday, January 16, 2007
Minimizing water absorption while traveling in the rain
I just did some very simple physics calculations (at the end of this message) and it appears that the simple movement of the bodies clearly yields let's water absorption with increased horizontal velocity. I believe that your results and "busting" of this myth are explained by 1) puddle splashing, 2) large lateral motions of arms, legs and head, and 3) the curving of the body w.r.t. the vertical.
1) Splashing water brings fallen water up onto the bottoms of the clothing,
2) Large lateral motions introduces a big surface area for catching more water.
3) A bent head and curved/slanted body greatly increases the area for the rain to fall on without substantial decreasing the forward surface area of the body.
My equations show that for speeds slower than the terminal velocity of water, the area on top should be minimized with the smallest vertical profile, while speeds in excess of this yield less water absorption as the body is tilted to increase the top surface area and thus minimize the frontal surface area.
This myth is not busted, and should be repeated with these three points addressed. I suggest that you conduct the run portion by:
1) Minimizing/eliminating the splashing, 2) Minimizing the movement of arms, head, and legs (range walk as they say in the Army, or in other words a very fast walk lacking the wild characteristics of running), and 3) Keeping the body straight vertically. I personally run through the rain with a mind to minimize splashes, minimize exposing extra surface area, and keeping my body fairly vertical.
The equations are as follows:
Q = rho * v, rho is the water density in air (constant), Q is the rate of absorption per unit of surface area, v is velocity
t = D / vx, t is the time for the trip, D is the fixed distance of the route, vx is the velocity of the subject in the direction of travel
m = Qy*Ay*t + Qx*Ax*t, m is the total mass absorbed, x and y subscripts refer to the directions of horizontal and vertical, respectively. The first term is the mass of water absorbed from the falling rain, while the second term reveals the mass absorbed from running into it.
m = (rho*vy) * Ay * (D/vx) + (rho*vx) * Ax * (D/vx) with substitutions from above equations
m = rho*D * (vy*Ay/vx + vx*Ax/vx) = rho*D * (vy*Ay/vx + Ax), thus small vx (walking slow increases the left term and gets you wet, while walking fast minimizes it and leaves you drier).
1) Splashing water brings fallen water up onto the bottoms of the clothing,
2) Large lateral motions introduces a big surface area for catching more water.
3) A bent head and curved/slanted body greatly increases the area for the rain to fall on without substantial decreasing the forward surface area of the body.
My equations show that for speeds slower than the terminal velocity of water, the area on top should be minimized with the smallest vertical profile, while speeds in excess of this yield less water absorption as the body is tilted to increase the top surface area and thus minimize the frontal surface area.
This myth is not busted, and should be repeated with these three points addressed. I suggest that you conduct the run portion by:
1) Minimizing/eliminating the splashing, 2) Minimizing the movement of arms, head, and legs (range walk as they say in the Army, or in other words a very fast walk lacking the wild characteristics of running), and 3) Keeping the body straight vertically. I personally run through the rain with a mind to minimize splashes, minimize exposing extra surface area, and keeping my body fairly vertical.
The equations are as follows:
Q = rho * v, rho is the water density in air (constant), Q is the rate of absorption per unit of surface area, v is velocity
t = D / vx, t is the time for the trip, D is the fixed distance of the route, vx is the velocity of the subject in the direction of travel
m = Qy*Ay*t + Qx*Ax*t, m is the total mass absorbed, x and y subscripts refer to the directions of horizontal and vertical, respectively. The first term is the mass of water absorbed from the falling rain, while the second term reveals the mass absorbed from running into it.
m = (rho*vy) * Ay * (D/vx) + (rho*vx) * Ax * (D/vx) with substitutions from above equations
m = rho*D * (vy*Ay/vx + vx*Ax/vx) = rho*D * (vy*Ay/vx + Ax), thus small vx (walking slow increases the left term and gets you wet, while walking fast minimizes it and leaves you drier).
Tuesday, January 02, 2007
Current energy issues
Concerning fission, there exists Helium-4, but Helium-3, having only one neutron, would be *extremely* unstable and any discussion of it would seem impractical; such a nuclear core would deteriorate in femtoseconds or faster. I have commonly heard of Hydrogen-3, also called Tritium, in discussions of fussion, so my guess is that this is the correct reference. Now, Tritium, also called heavy water, because it is usually harvested in that form, has enough mass to assist the process in slamming the nuleii together for fusion. The increased mass provides more momentum which resists the nuclear deflecting forces. Now continuous fusion has been around for at least a decade, but the duration of fusion has always been far too short to net positive returns on power. The reason for the brevity of the fusion process is that the incredible energy release quickly overpowers our ability to maintain the required pressures and temperatures. BTW, scientists have always projected fusion to be 50 years from the point in time at which they are asked the question about its viability. I just chalk it up to them saying that they don't know but they are seeing very slow progress.
On the oil issue, most of the world has been mapped with crude images (pun intended) and most of the significant, easy oil reserves are known. Now deep sea (past the continental shelves) has not been imaged or drilled very well and much of the land has also been practically ignored. It is kind of like taking large pictures of the whole sky and then looking deep into the sky at all of the places where you expect to see life (based upon rough theories of the development of life), and then (incorrectly) saying that you've found most of the life in the universe. Whenever someone talks about oil reservoirs, ask how their sizes and capabilities have been assessed for their numbers/claims. Do they include the proprietary data held secret by the oil companies as they implement their strategic business goals? I should think not. Do they include shale oil, oil sands, or oil on protected lands (say thank you to the environmentalists)? Protections on Alaska, and the entire region around Utah are being lifted as we speak. Do they include more difficult oil reservoirs, where 100 wells are required for the same production that one well used to generate? This is the situation for the new oilfields in northern Canada.
Now as far as shale oil, the method of extraction is mainly heat, but also pressure. The crude is brought to such a high temperature that it exits the pores of the fractured rock in a gaseous form, not necessarily as natural gas alone, including diesel, kerosine, gasoline, hexane, butane, and methane. All of these forms are easily separated and processed, according to the current petroleum needs. It is all a matter of chemically combining or splitting the carbon chains via organic chemistry, or of stripping off the hydrogen from the chains to generate hydrogen gas. Natural gas may be converted into gasoline or diesel (at a small expense) and vice versa, with the option to convert most of any of the forms into hydrogen gas for a hydrogen economy (see the hydrogen car or fuel cell). So the petroleum is extracted as a gas, but not necessarily "natural gas" and with a small expense, the desired form of "crude oil" may be synthesized from the purified shale oil extracts; the technology and methods have existed since the 1980's (when fuel prices went "through the roof" for a time) and are in use today. The only element of development these days is efficiency.
BTW, according to a recent article, the US shale oil reservoirs are estimated at around 97% (or higher) of the world shale oil reserves, and 7 times the crude oil estimates for Saudi Arabia, but again some knowledge affecting those numbers is guarded and additional knowledge from better and expanded geological imaging and interpretation both increase those numbers on a daily basis.
The question isn't when we run out of oil, but when the price of oil becomes uncompetitive with other energy sources (hydrogen not being a source, but a storage mechanism). My question is when are we going to start (safely) recycling our nuclear fissile fuel and thus slow our nuclear waste generation, which typically contains between 97% purity (military) and 99% purity (civilian) reactor fuel minimum requirement?
On the oil issue, most of the world has been mapped with crude images (pun intended) and most of the significant, easy oil reserves are known. Now deep sea (past the continental shelves) has not been imaged or drilled very well and much of the land has also been practically ignored. It is kind of like taking large pictures of the whole sky and then looking deep into the sky at all of the places where you expect to see life (based upon rough theories of the development of life), and then (incorrectly) saying that you've found most of the life in the universe. Whenever someone talks about oil reservoirs, ask how their sizes and capabilities have been assessed for their numbers/claims. Do they include the proprietary data held secret by the oil companies as they implement their strategic business goals? I should think not. Do they include shale oil, oil sands, or oil on protected lands (say thank you to the environmentalists)? Protections on Alaska, and the entire region around Utah are being lifted as we speak. Do they include more difficult oil reservoirs, where 100 wells are required for the same production that one well used to generate? This is the situation for the new oilfields in northern Canada.
Now as far as shale oil, the method of extraction is mainly heat, but also pressure. The crude is brought to such a high temperature that it exits the pores of the fractured rock in a gaseous form, not necessarily as natural gas alone, including diesel, kerosine, gasoline, hexane, butane, and methane. All of these forms are easily separated and processed, according to the current petroleum needs. It is all a matter of chemically combining or splitting the carbon chains via organic chemistry, or of stripping off the hydrogen from the chains to generate hydrogen gas. Natural gas may be converted into gasoline or diesel (at a small expense) and vice versa, with the option to convert most of any of the forms into hydrogen gas for a hydrogen economy (see the hydrogen car or fuel cell). So the petroleum is extracted as a gas, but not necessarily "natural gas" and with a small expense, the desired form of "crude oil" may be synthesized from the purified shale oil extracts; the technology and methods have existed since the 1980's (when fuel prices went "through the roof" for a time) and are in use today. The only element of development these days is efficiency.
BTW, according to a recent article, the US shale oil reservoirs are estimated at around 97% (or higher) of the world shale oil reserves, and 7 times the crude oil estimates for Saudi Arabia, but again some knowledge affecting those numbers is guarded and additional knowledge from better and expanded geological imaging and interpretation both increase those numbers on a daily basis.
The question isn't when we run out of oil, but when the price of oil becomes uncompetitive with other energy sources (hydrogen not being a source, but a storage mechanism). My question is when are we going to start (safely) recycling our nuclear fissile fuel and thus slow our nuclear waste generation, which typically contains between 97% purity (military) and 99% purity (civilian) reactor fuel minimum requirement?
Correcting the calendar and time conventions
Noting the odd convention of the leap year, multi-base (non-decimal) definitions of time units with seemingly arbitrary multiples which aren't always integers, and discrepancies between the conventional time for the average year of 31,557,600 seconds per year and the correct time per year of 31,556,925 seconds per year, one might resolve these very small temporal discrepancies in the time conventions by restructuring the standards of time so that one year measures the period of revolution of the earth around the sun with little need for corrections (every four years) and that each unit, like the metric system is a multiple of ten as opposed to the 60s per minute, 60 minutes per hour, 24 hours per day, 7 days per week, 4.4 weeks (constantly varying, but never an integer number, between 4-5) per month, 12 months per year, 52 weeks per year, etc.
With 31,556,925 seconds per year (365.25 days) in 2000 and 31,556,981 seconds per year (365.25 days) in 2100, the latter standard will be good for the next 200 years as an average to the year 2200. With 365 days per year, an extra 57.48 seconds is added to every day, yielding an average day of 86,458 seconds (86,400 currently). A new second can be defined as 0.86458 old seconds to yield 100,000 seconds in a day, which can be divided into new decimal based time units of 10 hours per day, 100 minutes per hour and 100 seconds per hour.
Given 365 days, we could follow the lunar cycle, with 13 months in the year, where each of the first twelve months has 28 days and the thirteenth month has 29 days. Or if we have an aversion to the number thirteen or to changing the number of months in a year, then we could define 5 days per week would yield 73 weeks, thus 12 months per year would allow 6 weeks per month for 11 of those months, with 7 weeks in the 12th month. These considerations have been made with the restrictions that the length of the day must remain relatively the same and that the year must extended to maintain itself from year to year without any need for leap year corrections, and that all units of time should been even multiples of each other with the preference of base ten numbers and a secondary preference of numbers similar to standard conventions when the primary preference is not ideally applicable.
With 31,556,925 seconds per year (365.25 days) in 2000 and 31,556,981 seconds per year (365.25 days) in 2100, the latter standard will be good for the next 200 years as an average to the year 2200. With 365 days per year, an extra 57.48 seconds is added to every day, yielding an average day of 86,458 seconds (86,400 currently). A new second can be defined as 0.86458 old seconds to yield 100,000 seconds in a day, which can be divided into new decimal based time units of 10 hours per day, 100 minutes per hour and 100 seconds per hour.
Given 365 days, we could follow the lunar cycle, with 13 months in the year, where each of the first twelve months has 28 days and the thirteenth month has 29 days. Or if we have an aversion to the number thirteen or to changing the number of months in a year, then we could define 5 days per week would yield 73 weeks, thus 12 months per year would allow 6 weeks per month for 11 of those months, with 7 weeks in the 12th month. These considerations have been made with the restrictions that the length of the day must remain relatively the same and that the year must extended to maintain itself from year to year without any need for leap year corrections, and that all units of time should been even multiples of each other with the preference of base ten numbers and a secondary preference of numbers similar to standard conventions when the primary preference is not ideally applicable.
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