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  1. mrspeedybob

    Stronger tubes using internal structure?

    That only works if the strengths of the inner and outer tubes add up simply. I don't know if they do or not, but I seriously doubt it. Sure, I can find the strength of a round tube and the strength of a square tube that would fit inside it, but I really doubt the total strength of the 2 put...
  2. mrspeedybob

    Stronger tubes using internal structure?

    On the topic of structural tubing... It is my understanding that round tubing is stronger than square tubing, or conversely that, that round tubing is lighter for a tube of the same strength. Does it necessarily follow that the best possible use of material when making a tube, is to use it all...
  3. mrspeedybob

    I What would happen if you moved a black hole?

    All motion is relative, therefore, moving a black hole is equivalent to moving yourself, so conduct an experiment... 1. Move. 2. Record your observations.
  4. mrspeedybob

    Revolutionary Physics experiments that changed the world

    Don't know who, where, or when, but at some point, someone had to conduct an experiment to confirm the feasibility of transferring an idea from one person to another via artificial graphical representation. This would have been the genesis of writing.
  5. mrspeedybob

    Increasing car efficiency by rerouting airflow?

    Sounds like you're essentially talking about a jet engine designed to generate just enough thrust to cancel out it's own drag, rendering the latter effectively zero.
  6. mrspeedybob

    I DDWFTTW: Looking for the least confusing explanation

    The air and the ground are moving relative to one another, therefore, they have kinetic energy relative to each other. It is possible to build an apparatus to harness that energy. Movement of the apparatus parallel to the air/ground movement necessitates certain design considerations, but does...
  7. mrspeedybob

    Permanent magnets still an open problem

    OK, I see what you're saying and I think we're on the same page. What you are describing is why random chunks of iron do not spontaneously self-magnetize. If you put a piece of iron in a magnetic field, though, now some of those tiny little magnetic particles find a lower energy state by...
  8. mrspeedybob

    Permanent magnets still an open problem

    This was not my experience playing with small magnets as a child.
  9. mrspeedybob

    Medical MBTI Personality Types

    I took this many years ago. I think it was pretty accurate, but with a couple of limitations. One limitation is that it condenses what is really a continuum, into digital designations. For example, the first letter is either an I for introverted or an E for extroverted, but there are no...
  10. mrspeedybob

    B Near-light speed and time

    The light clock explanation may make time dilation look like an illusion that occurs in that particular circumstance, but if you stop and think about what time actually is, in every way that matters, it is the rate at which things happen. The rate a clock ticks, the rate of radioactive decay...
  11. mrspeedybob

    Why an electron's drift velocity is so slow?

    If you look at any 1 electron it is almost as likely to be going up-stream (against the applied voltage) as it is to be going down-stream. The next question could be "why does an electron ever go against the applied voltage?" My answer would be that on a scale that small, random interactions...
  12. mrspeedybob

    I Batteries connected in parallel

    Most light and medium duty diesel trucks use 2 batteries in parallel in order to provide enough current to start the engine. Heavy trucks may use more, IDK. Batteries in parallel are fine as long as they're the same chemistry. 2 batteries in parallel is essentially the same as 1 battery with...
  13. mrspeedybob

    I Fans with 3 blades vs. 6 blades (noise, efficiency)?

    You could put them both on a skateboard, pointed in opposite directions, and see which way it moves.
  14. mrspeedybob

    B Mosquito radar

    Senty gun using a camera for target tracking would be cool. Many videos of DIY set-ups on youtube. Maybe you could adapt one of those designs to target mosquitos with a laser or something. Probably need a lot of careful fine tuning to prevent it from targeting you though.
  15. mrspeedybob

    News Breaking Down the 2016 POTUS Race Contenders & Issues

    May I ask for clarification? How do we discuss the 2016 election without discussing politics. What aspects are OK or taboo? Could you perhaps cite some post numbers where you consider the content in bounds and some where you consider the content out-of-bounds to give me a sense of what's what...
  16. mrspeedybob

    News Breaking Down the 2016 POTUS Race Contenders & Issues

    Pretty much. There may be rare exception. Later this weekend when I've got time I'll try to go through all the major stuff that the feds have done over the last 3 decades and explain how each one was a failure (or success). If someone else has more free time then I do and can beat me to it, go...
  17. mrspeedybob

    News Breaking Down the 2016 POTUS Race Contenders & Issues

    To be fair, GW didn't have much choice but to do something in Afghanistan. An act of war was committed against the US. The Afghan government was protecting the perpetrators. GW showed a lot more restraint than I probably would have.
  18. mrspeedybob

    News Breaking Down the 2016 POTUS Race Contenders & Issues

    Because every time the federal government does something, they screw it up and make things worse instead of better. This is due to the fact that the skills needed to get elected are not the same skills needed to perform the duties of public office. The solution to this problem would be for the...
  19. mrspeedybob

    News Breaking Down the 2016 POTUS Race Contenders & Issues

    Crazy scumbag will never get enough cooperation from congress to get any of his scumbagging done. Intelligent scumbag has some allies and will likely be able to coerce cooperation from others, hence, more scumbagging will get done. Best case scenario I think for the next 4 years is going to be...
  20. mrspeedybob

    News Breaking Down the 2016 POTUS Race Contenders & Issues

    Neither one of these candidates is fit for the presidency because neither one seems to have much respect for the Constitution. Both of their agendas I think are going to be harmful to the long term health of the country. All the vulgarity and accusations of cover-up are beside that main point...
  21. mrspeedybob

    I Time travel thought experiment

    Revive some of the original definitions of various units... 1 meter = 1/10000000 the distance from the north poll to the equator. 1000 Kg = weight of 1 cubic meter of water. 1 hour = 1/24 of a day etc... If you did go back with all the scientific knowledge, these original definitions should be...
  22. mrspeedybob

    Why are accelerating cars less fuel efficient?

    That may be true of an engine that is designed and built to run at WOT all the time, but an automobile engine is not. Up to 70% - 80% throttle, the fuel system is designed to run at stoichiometric air/fuel ratio. If it continued to run at stoichiometric ratio near WOT, the combustion chamber...
  23. mrspeedybob

    I How would dark matter aggregate?

    The only way we know about dark matter is because of its gravity. If there were a massless particle (like a photon) that didn't interact with the stuff that we and our instruments are made of, it wouldn't be surprising if we didn't know about it. The only way we could would be if it were needed...
  24. mrspeedybob

    I How would dark matter aggregate?

    You beat me to it. The other thing that I was going to ask is, how do we know dark matter does not radiate? We know it doesn't radiate EM because we can't see it, but what's wrong with the idea of another force or type of radiation that interacts with dark matter and not normal matter. DM had...
  25. mrspeedybob

    Time of free fall does depend on mass

    It is generally expected that inertial and gravitational mass are equivalent. The reason people are looking for a difference is because that would be big news. It's human nature to want to set yourself apart from the crowd. What better way to do that then proving that physics is radically...
  26. mrspeedybob

    Strong, flexible material

  27. mrspeedybob

    How to intuitively see the v^2 relation to kinetic energy?

    The amount of power it takes to push something is equal to how hard you push times how fast you push. So far that's pretty intuitive right? Accelerating something that's moving fast requires me to push fast. Accelerating something that's moving slow requires that I push slow. If I push equally...
  28. mrspeedybob

    Question re. flying against Earth's rotation

    Wouldn't this rather be a lack of circular motion? Traveling with the Earth's surface would be circular motion, and i'd expect some centrifugal force to partially cancel out gravity, that's why the Earth bulges at the equator. A plane flying against the rotation of the Earth would not experience...
  29. mrspeedybob

    I Fascinating use of physics to prove a math theorem

    I'm going to have to disagree with that premise... If I put an apple on a table, then put another apple beside it, then there are 2 apples. Hence 1+1=2. I can empirically observe that there are not 3 or 4 or more apples, nor are there 0 or 1 apples unless I get hungry. Based on these...
  30. mrspeedybob

    Seeing more than the visible light spectrum

    I was thinking more along the lines of training the brain to perceive multiple colors at the same spot, at the same time. Normally, our brains construct a 3 dimensional model of our environment from a pair of 2 dimensional images. However, the brain is amazingly adaptable. I was trying to think...
  31. mrspeedybob

    Seeing more than the visible light spectrum

    Cameras and false color displays pretty much the address original question, but there is a related idea that I've been pondering for a while. How would you go about "seeing" spectrums instead of averages colors? For example, being able to distinguish something that is green from something that...
  32. mrspeedybob

    AC Alternator Load Loss on Engine Performance

    Most automotive alternators are regulated to output 14 volts +/- 0.5 with a maximum current output in the 100 to 140 ampere range.
  33. mrspeedybob

    Will two lasers deliver exactly double the heating?

    Even if the 2 beams do interfere with each other destructively, the energy absorbed by the target should still be the sum of the 2 beams. If it less, then where did the non-absorbed energy go?
  34. mrspeedybob

    Using instantaneous torque to determine energy

    You stated you were trying to "chart energy consumption instantaneously", but measuring the torque and angular velocity of the motor output won't give you that. It will give you mechanical energy output which will only be a lower bound on energy consumption. Consumption and output will always...
  35. mrspeedybob

    Will this travel faster than light

    A better way to look at it is to understand that the faster you go, the slower your clock ticks as seen by someone who is not moving. If you were to get to the speed of light, your clock would stop. This is a statement about the nature of time, not just the nature of clocks. If you accelerate...
  36. mrspeedybob

    Just a Thought About Tornadoes and Wind Turbines

    I know you're probably thinking that the cost effectiveness of converting storm energy into usable energy is almost secondary. If I can spend $10 million on windmills that produces only $5 million worth of electricity, that may still be cost effective if removing that energy from the storm...
  37. mrspeedybob

    How to lift water up to 5 metres without using a pump?

    What is your definition of a "pump"?
  38. mrspeedybob

    Do Photons from one star affect other stars?

    I remember Susskind, in one of his lectures on youtube, discussing the effects of radiation pressure on cosmological expansion. The effect was significant in the very early universe, but ceased to be so long before the formation of stars. I'll try to go back and find the specific lecture and...
  39. mrspeedybob

    B Braking Distance, Skids & ABS

    ABS systems come in 2, 3, and 4 channel varieties. 2 channel systems control the wheels in pairs. These systems are the norm in small front wheel drive economy cars. Each front wheel is paired with the rear wheel on the opposite side. 3 channel systems are the norm on mid range cars and...
  40. mrspeedybob

    Challenge Micromass' big statistics challenge

    #5 I would expect the ball numbers (on average) to be evenly spaced through the range of possible ball numbers. The highest ball in this particular question is 213, so the average spacing between the numbers is 213/5. The total number of possible balls should include 1 average space above the...
  41. mrspeedybob

    Challenge Micromass' big probability challenge

    #3 I would expect the ball numbers to be distributed randomly though the range of possible ball numbers. Since they can be put in numerical order, regardless of the order picked, then let b1 be the smallest ball, b5 be the largest ball, and t be the total number of balls. I would expect that on...
  42. mrspeedybob

    B Da Vinci's flying machine meets solar sail?

    Instead of a rotating blade, simplify the mental picture to a 1x1 meter square sail. The sail is operating in a region of space with a photon density of 1 photon / m3. The photons are all moving in the same direction, perpendicular to the sail, so the sail is hit by 3x108 photons / second. Each...
  43. mrspeedybob

    B Da Vinci's flying machine meets solar sail?

    That would be true for a stationary angled blade, but a moving angled blade would blue shift the reflected photons. I'm thinking you could gain a little more Δp from the blue shift then you'd loose to the change in angle. I'm pretty sure most of us could do the math to actually figure this...
  44. mrspeedybob

    B Da Vinci's flying machine meets solar sail?

    I think it may be useful to think of the light as a kind of photon-gas tail wind. If the blades of the fan are flat, then I agree, rotating would not change anything. However if they are angled like fan blades, then thy could sweep a greater volume of the photon gas then flat, stationary blades...
  45. mrspeedybob

    Photons always take the quickest route

    No coincidence. It turns out to be the result of something fundamental about quantum mechanics. Feynman explains it in lecture 2 of this series... If it's not making sense, and you need some more background go back and watch #1 first.
  46. mrspeedybob

    Horse Racing calcuations

    Any of the figures MikeGomez calculated would come to 0.2 when rounded to the nearest tenth, so saying .2 second per horse-length is correct as long as you understand that 0.2 is not the same thing as 0.20
  47. mrspeedybob

    B MotoGP and knee sliders

    besides that, a wheel has a preferred direction of travel. Suppose the riders knee touched down and the wheel was not pointed exactly parallel to the direction of travel. This could easily throw the rider off balance and cause an accident. An answer to this could be to use casters or spherical...
  48. mrspeedybob

    B Have we observed antimatter in the early universe?

    But why do we think the energy came from particle/antiparticle annihilation? Why does it make more sense to say there were 2 billion + 1 particles and 2 billion of them annihilated to become energy, instead of saying there was 2 billion +1 units of energy and 1 of them condensed into a particle...
  49. mrspeedybob

    B Have we observed antimatter in the early universe?

    Why wouldn't the matter / antimatter production be exactly equal? And if wasn't exactly equal, why would we presume that it was approximately equal?
  50. mrspeedybob

    Can gravity be reflected

    IF we ever get a unified field theory, it should give some indication of whether gravity can be manipulated in some way (other then manipulating mass-energy distribution). It is possible that no U.F.T is possible if gravity is actually a fundamentally different thing the the other fields.