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Gweedz

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About Gweedz

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  • Favorite Area of Science
    Physics
  1. What about birds and insects? Would their navigation be screwed up, possibly leading to chaos and mass extinction? Would the GPS system still work? If the ocean currents and prevailing winds change I can see huge ecological disaster happening. I wonder if it will affect crops in any way. Plus, all our sundials will be out of whack!
  2. Say we wake up one day to find the earth rotating in the opposite direction. What would be different besides the sun rising in the west? Ignore the physics of accomplishing such a feat and let's assume everything has stabilized (tides, winds, etc). Just wondering about the effects - especially on the living things. In a similar fashion, what would be different if our path around the sun changed direction?
  3. If this were the case then if all ambient light is removed (say in a dark garage) and there was only one light source (say a small bulb on the floor), it should reflect more defined in the white car than black? I'm trying to devise an experiment I can do to show white is more reflective than black. By reflective I mean "mirror like". Because so far all my observations prove contrary to that, and contrary to what I was taught in school. Assuming the surface quality is the same between the two paint jobs, I would expect the same clarity (but at different contrast). Sorry about that - when I was saying "projector" I was actually referring to the projector "screen". I edited my post to hopefully make it less confusing. Thanks for catching that.
  4. A white screem shows black by not reflecting light. This is why the darker the ambient lighting, the deeper the blacks. Put the screen in sunlight and everything is washed out. So using the projector screen analogy - it would mean a white car at night should be ideal for showing an image. But the black car at night still provides a clearer (more defined) image. I tested this one night by standing close to my dark blue car and shining an LED flashlight downward to the door at a 45 degree angle. There was a clear light circle on the ground. When doing it to my neighbor's white car I got a huge diffused reflection - almost unnoticeable reflection. I'm tempted to say it is a physical property of the pigments but then again this also happens with glass and a black or white sheet behind it.
  5. Go to a new car dealership and you'll see all the back (and dark) cars with an almost mirror-like reflection on the body, yet the white cars just look white. "Common sense" would indicate white would reflect better. Why the disconnect?
  6. Thanks Spyman for the explanation - I'm still processing the info. The following will help me: I removed the switch and L2: ┌─────────────────────────────────────────────────────────┐ I │ + │ B] - │ I │ └──────────────────────────(L3)───────────────────────────┘ When you connect the battery, with L3 light (even temporarily)? ┌─── I + - │ I │ └──────────────────────────(L3)───────────────────────────┘ How about now?
  7. This was your response to my question: "What if we remove lamp L2, creating a break in the circuit. Will L1 and L3 still light up? For how long?" I'm still trying to wrap my head around this. If there is still a current then I take that as L1 and L3 will still light up and stay lit "until the potential has equalized". So while they're lit, they are fully functional in an open circuit (doesn't make sense, but I'll play along). And since the circuit is open the wires are independent of each other. So if they're independent then it shouldn't matter if you completely remove one wire. But now you're left with a single wire connected to a single battery terminal and it lights up fine (until the potential has equalized). That makes no sense... what am I missing?
  8. Are you sure about this? What if we remove lamp L2, creating a break in the circuit. Will L1 and L3 still light up? For how long? What happens if you move the switch to immediately before L1?
  9. Wow, I wasn’t sure what direction this would go but some very interesting points here. I’ve been thinking about this on and off for quite a while now, but my paths always fall into one of the following scenarios: SCENARIO 1 The lamp illuminates one year later - as soon as current flows through it. At this time it doesn’t know (or seem to care) if the circuit it complete or not. We have a fully functioning open circuit!? Imagine the possibilities (oh and “circuits” would be a misnomer ). SCENARIO 2 The lamp illuminates in 2 years when current has made a complete circuit back to the battery. How does the lamp “know” it took the return current 1 year to reach the battery? Is some other “info” sent back to the lamp saying “circuit it good, you can light now”? If so, then it would take 1 year for this info to travel, so the lamp would really take 3 years to light, not 2. Yet it would take only 1 year for it to turn off after the battery is disconnected. Something doesn’t add up. SCENARIO 3 Current flows from both terminals simultaneously (pushing and pulling as someone here described). It would take 1 year for the lamp to receive both “currents” knowing that the circuit it complete – it will illuminate. But as someone here hinted what if the lamp position was not equidistant from the terminals? Now the lamp is receiving one current before the other – which is basically identical to Scenario 1. Or, if it received one current but does not illuminate until both currents join, then we’re back to Scenario 2. And I'm back to being confused.
  10. Imagine a very basic DC circuit consisting of a battery, a bulb, and 2 wires connecting them. The wires are each 1 light year long (yes, a huge circuit). You connect everything together, then attach the battery... How long would it take for the light to illuminate (ignoring wire resistance, battery capacity, etc)? 1 year for the electricity to get to the bulb, or 2 years for the circuit to be completed? Depending on the reply I have follow up questions. Thanks!
  11. Does what I said in my previous post make sense? Because if it does then I have some follow up questions. Thanks.
  12. With your explanations and by rewording the problem in simpler terms I think I understand the issue as follows: Think of a ball traveling through space with string attached behind it. They are both traveling at constant speed, in unison, the string is straight yet relaxed. The ball and string travel by me, and before it passes I grab the end of the string (opposite of the ball) and hold it tight. I imagine from that instant the string will begin to feel tension and an elastic wave will travel towards the ball. However, until the wave reaches the ball, the ball has no idea the other end of the string is not moving, so it keeps traveling with the same vector. Once the wave reaches the ball it will begin to slow down, and eventually stop and reverse direction. Let's assume the string is 750 miles long, and the ball is traveling at 100 mph. The wave (traveling at approx. 750mph) will take 1 hour to reach the ball. During this time the string would have stretched 100 miles (13%) before the ball begins to slow down and reverse direction. If all this makes sense then I think I can use it to explain the yo-yo problem: Using the same criteria (750 miles, 100mph), as soon as the yo-yo reaches the end of the string it will send a wave back along the string. It will take 2 hours for the wave to make a round trip (ignoring the extra length of the stretched string). During these 2 hours no observer of the yo-yo can determine if the other end of the string is fixed or free. The yo-yo keeps slowing down (due to weight of string I guess). But shortly after the 2 hrs the yo-yo will either continue slowing down (fixed), or it will maintain a constant speed (free). This is the earliest an observer can determine the state of the other end of the string. The above scenario is valid regardless of string length and yo-yo speed. Did I get it?
  13. Also, maybe it's easier/cheaper for a small airport to get regular fuel vs av gas.
  14. I was going to say "lets assume the string has no elasticity", until you mentioned it's a requirement for special relativity. So in that case does it mean that once all the slack is taken up, the string begins to stretch? And will continue to do so for a long time (that approx. time for sound to travel more than 2 light years (2 lengths of stretched string))? And when the "information" is received at the yo-yo that the other end is tied, will the yo-yo basically be at zero velocity at this time, and begin traveling back up the string?
  15. I'm not into airplanes (but I know about engines), just some suggestions: A turbofan may have less parts, but due to speed and tolerances each part must be built with higher precision and better materials. Equals more cost. Small airports are more likely to have mechanics and tools suited towards older, established technology. (Same idea like that town in the middle of nowhere may not have a qualified mechanic or tools to service your 2012 Mercedes). Is a turbofan more reliable? (I really don't know, but I'd rather a couple spark plugs fail in an 8 cylinder engine, than a couple fan blades in a turbofan). Are most of the planes you see recreational planes where performance, speed, fuel economy, and range are not as important as a commercial airplane? For recreation some people like driving their classic cars, even when their daily driver vehicle is much better in all aspects. Is a turbofan too noisy for small airports near residential areas? Just some ideas, but I think the biggest reason is cost - for the engine, repairs, maintenance. With little added value to the operator/owner.
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