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    Finding mass of paperclip using Millikans theory

    Assuming all the paperclips weighed the same, wouldn't it be fair to say that the mass of an envelop filled will a random number of paper clips will have a mass equal to the sum of the mass of the envelop and an integer multiple of the mass of a single paperclip? In otherwords, if the mass of...
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    Frictionless physics problem

    1) Here are the equations you need: Circumference = 2*pi*Radius Speed = Distance / Time Centripetal Force = Mass * (Speed^2) / Radius So, if you know the Centripetal Force, what do you think the tension on the rope would be? 2) You should be able to use the equation for centripetal force I...
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    Proof: 0.9999 does not equal 1

    You are correct, I only proved that a proof commonly used is incorrect. The title was misleading.
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    Proof: 0.9999 does not equal 1

    http://en.wikipedia.org/wiki/Reductio_ad_absurdum
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    Proof: 0.9999 does not equal 1

    The function y=1-1/x is often used to show how the repeating decimal 0.9999... is equal to 1. When x=1, y=1; x=10, y=0.9; x=10000, y=.9999, and so on. The limit of 1-1/x as x approaches infinity equals 1. An assumption is often made, however, that if the limit of an expression as x approaches...
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    Digital and quantized signal, are one same thing?

    Generally, yes, but it depends. Digital audio is a quantized signal, but class D amplifiers (which quantize in the time dimension) are not considered digital. I guess you could think of digital as complete quantization.
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    Classical Physics with Time going Backwards

    http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=AJPIAS000074000004000313000001&idtype=cvips&gifs=yes [Broken] From abstract: "the equations of motion of charged particles are invariant under time reversal" If only I could read it without paying $$$. Was there something...
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    Classical Physics with Time going Backwards

    I thought magnetism just negated.
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    Classical Physics with Time going Backwards

    Of course that goes beyond classical physics. As far as we are concerned, the exact path taken by a boulder as it falls off of a cliff and smashes is reversible.
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    Classical Physics with Time going Backwards

    Well, any scenario where time goes forwards also follows the laws of physics with the same scenario running backwards.
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    Classical Physics with Time going Backwards

    First, what does it mean for time to be going backwards? Basically, any time there is a reference to time, we just need to negate it - so time will have a negative effect of what it usually would. Velocity (1D): There is an object that moved from A to B in time t at a constant speed. If we...
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    Distribution of Primes

    Yeah, I neglected the "at least for small numbers" in my second post.
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    Distribution of Primes

    I know. It's more likely than random, but that's about it.
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    Distribution of Primes

    I made this simple program to list all non-primes (ignore the first row and column of the output) and list what I call "important numbers". I have attached an output if you don't want to bother running and compiling the program. #include <iostream> #include <fstream> using namespace std...
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    Excluding Evidence contrary to Theories

    That doesn't seem like it could be it. In this video, it doesn't look like he is holding anything: Of course he doesn't show any of his wiring and cuts out the video frequently, so it's certainly possible he has a hidden power source somewhere. I just don't understand why that MIT professor...
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    Excluding Evidence contrary to Theories

    This one: https://www.physicsforums.com/showthread.php?t=213780 Of course the evidence is not the most reliable, but I would think a discussion on its reliability would at least be allowed.
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    Excluding Evidence contrary to Theories

    Recently, a thread here was closed because it linked to an experiment that seemingly conflicted with the currently accepted theories. While the majority of people agree with these theories, I think it is an injustice to censor evidence that is contrary to a theory - otherwise human knowledge...
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    Canceling out low frequencies noises (subwoolfers)

    You could always just go talk to the guy and tell him it's bothering you. That's better than calling the police over it. Other than that, you could decrease the air pressure in the room you are in :D
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    Wavelength in Orbit

    I'm not asking a question, simply making an observation. As for the diagram, the three rectangles on top of each other (labeled 1, 2, and 3) are sequential images of the impulses advancing and the object moving perpendicular to the direction of the wave. In frame 1, the object is experiencing...
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    Wavelength in Orbit

    Have a look at this diagram I made: http://la.gg/upl/wavelength2.jpg [Broken] The scenario is that you are in circular orbit around the Earth and a radio signal is sent from the center of the Earth. If you have a clock with you that is synced up to a clock on Earth (we are ignoring relativity...
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    C/C++ C++ Matrix Solver

    I just thought I'd post this here. It will help you solve a matrix by getting it into row-echelon form (well, close to it anyway). I avoided global variables and tried to make it as expandable as possible. #include <iostream> using namespace std; void output(int height, int width, long...
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    Quick question about light waves

    They would return to the values they had before entering the glass, as you suspected. EDIT: Looks like Claude beat me to it
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    Blueshift + Classical Physics = Golden Ratio

    L is the distance from (A) to (B) that observers on (A) would measure if only classical physics applied and both (A) and (B) were stationary. L is not the distance of (B) away from (A) at the time of the emission of the light signal, but the distance of (B) away from (A) at the time of the light...
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    Blueshift + Classical Physics = Golden Ratio

    I was doing calculations to see how far classical physics would take us in terms of the speed of an object never exceeding the speed of light in a reference frame. Here was the scenario I set up: http://la.gg/upl/light.jpg [Broken] So, if we want to find the time it takes the light to get...
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    Rearranging an equation

    Well, it's good he decided to chroot before doing an rm -rf /* :smile:
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    Chain consisting of five links

    You can use a singe F=ma to describe the net force applied to the entire chain, and if the only forces acting on the chain are the force pulling the top link pulling up and graving pulling the entire chain down, the net force acting on the chain = the force pulling up on the top link of the...
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    Diffusion of Different Gases/Particles through Air

    If something like oxygen were to be released into a room, it would diffuse much faster than something like a heavy smoke. Has someone ever measured the rate of diffusion of different gases and particles? A quick Google search turned up nothing. I'd like to know the distribution of how many...
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    Some true and false questions

    :D Already made the edit
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    Some true and false questions

    You are definitely right about #1 #2) You are right #3) If this question writer is an a$$hole, he may count a net force of zero #4) You are right about this one. The forces would be equal #5) You are right #6) Ah, speed is used instead of velocity. Velocity is a vector, while speed is a...
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    Some true and false questions

    It looks like you have the right idea.
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    Does light exerts force?

    I think what you are talking about is called a radiometer. What causes it to spin is not the change in momentum from light "particles" hitting the paddles. In fact, the black side of the paddles absorbs much of the incoming light, causing the black side to heat up, while the white side stays...
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    Does light exerts force?

    I don't think that light produces any force directly from its motion. The energy from light can cause a force to be generated, however. What exactly is your project?
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    Can absolute zero ever be achieved?

    Great post Count Iblis! I agree with what you are saying.
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    Pure electrostatic

    To create a transformer to change the voltage, you want to have the proportion of the number of output windings to the number input windings equal to the proportion of the output voltage to the input voltage. You can't reduce the current to truly be zero and still have anything flow, which...
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    Toboggan Speed Theory

    Yes, and F=ma. Heavier people (assuming all else equal and that the fluid dynamics involved don't cause anything funky to happen) will accelerate faster than lighter people because the fixed force of air resistance will have less of an effect in terms of acceleration on the larger mass, but the...
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    Toboggan Speed Theory

    Also, the force due to air friction slowing down the tobogganers is dependent on speed and surface area, not mass, but the force due to the combination of the normal force of the slope and gravity will be greater for heavier people, meaning heavier people of the same size and shape would be...
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    Doppler Effect.

    If you want a way to think about why this must happen, you can think about it this way: In a given time period, the train has traveled a certain distance determined by its speed. Let's assume this train produced only two clicks, one at the starting point and one at the ending point. If you had...
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    Electical shock, electrocution questions

    1) I'm not sure if this is the best answer, but air is a much better insulator than your body and your hand, so even a convoluted route through you and back out the other half of your finger will have less resistance than a path through only the air. 2) If there is a drain in this pool, and the...
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    Can absolute zero ever be achieved?

    Well, it would be a violation of the Heisenberg uncertainty principle if you could detect the existence of such a particle. I don't see how its sole existence would violate it. Also, thermodynamics seems to be a field of probability. While energy tends to flow from high to low on average...
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    Calculating Normal Force

    The formula typically used for this scenario is (The Force of Kinetic Friction) = (The Coefficient of Friction) * (The Normal Force) For the weight of the block, you should realize that both weight and force are the same units. For an object resting on a horizontal surface the normal force and...
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    Sound Intenisty at a Football Game

    I think it's safe to assume that everyone is located an equal distance from the center of the field (otherwise we'd need more information). The first trick is to look at the decibel scale. dB is a logarithmic scale in reference to the power of the sound. If the power of two sounds are power1...
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    Budding SciFi Author with many questions

    In terms of paraterraforming, I would think this would have to be set in the far distant future. Unless the population gets so high that there literally isn't enough room for everyone, it seems a little impractical. On Earth we already have tons of land, a decent atmosphere, and close to the...
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    Drag can happen in extremely low-viscosity fluids

    Okay, here is my statement: "Even if the molecules in a fluid did not collide with each other, there would still be drag." It seems I misread some of the things russ_watters had posted, and thought he was arguing that Thomas2 was wrong that there would be drag if the molecules in a fluid did...
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    Faster than light.

    If you rework what I did here with another distance in place of 1/2 of a light year: https://www.physicsforums.com/showpost.php?p=1584381&postcount=18 You will find that the speed you get is the same. So, distance doesn't matter with my calculations either. That doesn't prove that the distance...
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    Faster than light.

    Tell me, how do you measure velocity? EDIT: This is the main purpose of Lorentz transformations: http://en.wikipedia.org/wiki/Lorentz_transformation#Spacetime_interval The idea is that the Lorentz transformations allow you to convert measurements from one observer to another when time is not...
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    Faster than light.

    Why? Because then the distance between two events in space-time would not be the same for all observers. The theory of special relativity postulates that c is constant (it did not prove it) to make the math work out nicely.
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    Faster than light.

    Of course you don't with the Lorrentz transformations. This is because each planet sees the other planet as being closer than it really is. Notice how in this example below, the perceived speed is lower than the actual speed:
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    Drag can happen in extremely low-viscosity fluids

    The balloon talk was necessary for people to understand the number of collisions of air molecules with you every second. Otherwise, my explanation of drag would have made little sense.
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    Faster than light.

    Let me rephrase what I said: Scenario 1: Planet A is at location 0 Planet B is at location -1ly Planet A sends a beam of light at c towards Planet B Planet B moves towards Planet A at close to c ================ Planet B will receive the light in a little over 1/2 year Scenario 2: Planet A is...
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    Faster than light.

    Now, we could just as easily have a planet going very close to c towards us (only slightly less) instead of the light. Okay, so now if two planets 1 light year apart were traveling as close to c as possible towards each other, they could meet in only a little more than half of a year. Let's say...
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