• Content count

  • Joined

  • Last visited

Community Reputation

0 Neutral

About SgtLongcoat

  • Rank
    Advanced Member
  1. While it might not be a major pastime for me, I enjoy learning about magic. Not of the satanic ritual variety, but of the slight of hand, stage/street variety. Sometimes I like to use this to harass my friends with impossible tricks, other times I just do it to practice some fine technical skills. In this case, namely how to throw playing cards. If you have a deck, go grab it right now, and try to throw a card. Watch, as it flops to the ground like a piece of paper. Now, grab it by the corner, and try throwing it like a frisbee. Suddenly, the card will move in a straight line or arc, and, depending on what you're throwing it at, lodge itself in its target. Why does this change in motion change the outcome of the throw? To explain it simply, by spinning the card, the angular momentum of the card prevents it from being easily rotated in another direction. Combine it with the low air resistance that you create on the card's edge when throwing it in such a manner, and the air resistance prevents the card from actually fluttering down like it would if not spinning. While I'm on the topic, let me mention that, while it could stick in the right target, a playing card CANNOT be used as a weapon. Due to its relatively low mass, it would lack the sufficient energy necessary to cause more than a small paper cut to the human body. If you don't want to believe me, however, know that this myth was tested by the MythBusters, and a card launched at 150 mph by a machine didn't have enough energy to cause more than said paper cut.
  2. The Phoenix Wright: Ace Attorney series is one of my personal favorite sets of logic/puzzle games of all time. Going through the cases one by one, you begin to feel like a real Sherlock Holmes... if Sherlock made wild accusations in order to buy a little time to find proper evidence which may or may not actually support them. And if Sherlock Holmes involved a bunch of quirky witnesses and pop culture references. And if Sherlock Holmes took place in a universe where California and Japan are somehow the same thing. And if... well, you get the picture. Being one of my favorite games, however, does not excuse it from defying the laws of physics. The specific instance I refer to (being the game includes ghostly possession which transforms the channeller's body into that of the spirit and telekinetic lifting of rubble which came from absolutely nowhere) occurs during the first case of the fourth game. In this case, the victim was murdered with a glass grape juice bottle (not actually a censor for wine, as cases in later games both include alcohol and outright confirm that the grape juice is of the "non-fermented" variety), resulting in death via cerebral hemorrhaging due to blunt force trauma to the forehead. All well and dandy, right? Except that the bottle was both fully intact and fully empty. So, I got to wondering if this were actually possible, when I found the results from an old MythBusters episode where they tested something pretty similar. They wanted to know if a full or empty bottle would cause more damage to the human skull. To sum up their results, the empty bottle generated less G-force during an impact (28.1 G as opposed to 22.7 G, natural, as it weighs less), could not break a simulated human skull, and DEFINITELY broke when smashed against the simulated head. While the in game autopsy confirms the cause of death, this creates a contradiction with real life physics. Either the bottle wasn't hit hard enough to break, and therefore shouldn't have caused blunt force trauma, or the bottle was hit hard enough to cause blunt force trauma, and therefore should have broken. While this can likely be attributed to a different makeup of the structure of the glass, I'd be more inclined to believe that this was done due to necessity, as the position of the defendant's fingerprints proves integral in the trial, which means a broken bottle would make certain things much harder to prove. In addition, as with all video games, rule of fun trumps all rules of physics.
  3. As many video games attest to, sometimes firing a weapon doesn't have any effect whatsoever on the shooter's momentum, even in the cold, dead vacuum of space where there's NO OUTSIDE FORCE TO CORRECT THE FORCE DUE TO IMPULSE! Impossible, no? Well, in some cases, no, it's not quite impossible. While many might immediately think of rocket launchers, which are self propelled, and therefore would have minimal effect on the momentum of the shooter, these are not classified as recoil-less weaponry in the traditional sense of the term. Recoil-less weapons, specifically rifles, fire modified artillery shells which still behave as a simple projectile after leaving the weapon. How does this work, then? While a normal rifle would cause the gasses inside the bullet to expand in a closed chamber, propelling the bullet forwards at high speeds out of the barrel, recoil-less rifles allow for some of the gasses to escape out the rear of the rifle, compensating for most of the recoil which would normally result from launching a projectile. This actually allows for two different side effects. First, this allows for the removal of heavy recoil mechanisms and the reduction of weight of the barrel. Second, it reduces the velocity of the launched projectile. In order to compensate for this, most recoil-less rifles launch a much heavier projectile a shorter range, in order to take advantage of the relatively light weight of the rest of the weapon.
  4. You forgot about torque, which would eventually cause the poor guy to land either face-first or rear-first on the pavement, especially considering the power and weight of a machine gun.
  5. So long the direction of motion didn't change, the human body could most likely handle it. If the body accelerated upwards or downwards would cause the only real problems, as the blood would rush to the feet or head, causing a black-out or red-out, respectively. And a red-out is especially dangerous, by the way, as the excess blood in your head can cause severe damage to the brain. Aside from that, however, we also have to keep in mind that length of an object drastically decreases at high speeds, meaning that there's the possibility for some adverse effects on the human body from compression, but seeing as how speed of light travel is a long ways away, the last part is just conjecture. As for the original post, some scientists believe backwards time travel may be possible, but only if an object could travel faster than the speed of light. Considering 3 x 108 m/s is sort of the universal speed limit, that may be impossible, and is definitely not testable with our current means and methods.
  6. I love this game, and I have to agree with you that falling so far would hurt a real person, but do you really want a game with such a simple premise to add in broke bones to its mechanics? You'd essentially be walking around for weeks at the very least with a limp that would slow you down, and at worst in a wheelchair, meaning it would be hard to actually farm at all.
  7. As anyone who's ever heard the story of William Tell can attest, shooting an object with extreme precision, especially something like an apple off of someone's head, with a bow and arrow takes a ton of skill, practice, and luck. It gets even crazier when you see somebody shoot an object the size of a dime flying through the air. Just how do stunt archers do this? First of all, its nowhere near as easy as "train until you are 100% accurate," as arrows don't fly straight. What's that? Years of high school archery in gym proves otherwise? Well, first of all, congratulations on actually being able to aim, and second of all, you're only examining the arrow's flight path as a whole. Yes, the arrow's center of mass does behave like a simple projectile, so, for larger targets, its fine. However, as the arrow flies, the shaft of the arrow actually bends back and forth in a motion resembling a wave. This motion actually is what enables the arrow as a whole to fly in a straight line, as it otherwise would simply fall flat on the ground. As such, stunt archers need to be able to figure out where the arrowhead will be when the arrow travels to its target. This, believe it or not, can actually be brought down to a science. Simply by knowing the strength of the material that the arrow is made of, as well as the distance between the arrow and the target, archers can accurately predict if the arrowhead will actually be in the right position to hit the target. As such, most stunt archers actually use a device to measure the strength of said arrow, and will only shoot with arrows falling within a very specific range.
  8. So then, the type of display found in calculators would rely on the reflection of outside light to actually display stuff, right?
  9. My only question: How does the screen realign the liquid crystal such that it can actually produce the proper color?
  10. In the Borderlands series, specifically Borderlands 2 and Borderlands: The Pre-Sequel, corporate villain Handsome Jack and the company of Hyperion use a device on their moon base/corporate HQ to launch supplies and killer robots down to the planet of Pandora and its moon, Elpis. But just what is said device? During the beginning of Borderlands: The Pre-Sequel, you get the luxury of being shot out of the moonshot cannon in an emergency evacuation. Fun! But, in the chamber for the moonshot, there is no visible propulsion device: no explosive charge or rocket to launch it. So what does propel the moonshots? Simply put, the moonshot cannon acts as a railgun. So, how does a railgun work? By connecting a projectile between two long rods, and running a current through the rods, it's possible to create an induced magnetic field which launches said projectile without the need for a conventional propulsion mechanism.
  11. This is pretty interesting. So, being speakers operate based on electric signals and magnetism, is the pickup sort of like a reverse speaker, where the sound moves a magnet, causing electric signals, instead of the other way around?
  12. Many have seen the Back to the Future trilogy, in which Marty McFly and Doc Brown use a modified DeLorean to travel through time. According to Doc Brown, the machine requires "1.21 Jigawatts" of power (confirmed by the directors to simply be a mispronunciation of Gigawatts) to power the flux capacitor, which enables time travel. This is achieved by bringing the DeLorean up to a speed of 88 mph, roughly 39.34 m/s. Using this information, I will do what any sane person would do: calculate the mass of the DeLorean. Before I can calculate the mass, there are a few missing pieces I need to know or assume. First, the coefficient of friction between the tires and the road. Considering that roads at the time were mostly made of concrete, it's safe to use the coefficient of friction for rubber on concrete, which will be somewhere between 0.6 and 0.85. Being the car is in motion, and the wheels are rotating, the static coefficient of friction should be used, so I'll take the higher value of .85. Second, I'm going to assume that air resistance is negligible in this case, and that all work done on the DeLorean comes from the force of friction, which is used to accelerate the car forwards. Finally, I'm going to assume that the DeLorean moves with a constant acceleration, such that the average velocity of the car is equal to half the final velocity, or 19.17 m/s. With that done, I can work backwards from the beginning to determine the DeLorean's mass. First of all, being power can be calculated using the equation P=F•v, and the net force on the car and velocity of the car are in the same direction, Net Force = P/v = 1.21 x 109 W / 19.17 m/s = 6.31 x 107 N. Being friction is the only force acting to accelerate the car, this is also the force of friction. Now, being the force of friction = µ(Force normal) = µmg, the mass of the DeLorean = Ffriction / (µg) = 6.31 x 107 N / (0.85 x 9.81 m/s) = 7.57 x 106 kg. Looking up the actual value for the mass (yes, you can find it), it's about 1230 kg, a large discrepancy. While the assumptions made above, especially concerning air resistance, don't help the numbers, the fact of the matter is that Doc Brown never fully explained how the DeLorean worked, so it's almost impossible to calculate a realistic number for its mass. Besides, would you really want him to? If so, be prepared to sit through a full movie dedicated simply to explaining the science behind it before even beginning the actual trilogy.
  13. The bigger question is, would we be dumb enough to blow up the only planet we can currently live on?
  14. Interesting. So, do shock waves in water act similarly to sound waves, then?
  15. In the previous post, I referenced a quote from Toy Story, said by Woody after Buzz is first introduced, in response to Buzz's stunt around Andy's room. If you haven't seen the first Toy Story (which I don't know why you wouldn't have by now) turn away now before I spoil a minor part of the end of the movie. You know who you are. Alright, here it goes... At the end of the movie, Woody and Buzz are trying to get back to Andy, and have to chase a moving van on RC. In the process, Buzz lights a firecracker that was attached to his back, sending him and Woody into the air to eventually fly down into Andy's car. Simple, right? Well it is, until you realize that Buzz and Woody, even if you refer to what they did as gliding, shouldn't have been able to stay aloft. Disney's artistic physics license implies that Buzz's "wings" were enough to keep both him and Woody aloft, due to air resistance. While the pressure differential above and below the wings due to moving air would cause that in real life, the shape of Buzz's wings don't allow that. Because Buzz's wings are flat, the amount of air pushing up on the wings will equal the amount of air pushing down on the wings. If you don't believe this, just look at any airplane. The curvature of the wings is what allows air resistance to keep the plane aloft in the first place. In short, Buzz's flight was impossible, and would have been even more difficult while carrying Woody.