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Everything posted by m4rc

  1. An example that infinity/infinity=anything let a=the total number of integers let b=the total number of even integers both a and b are infinite but a is twice as large as b so, a/b=infinity/infinity=2 and b/a=infinity/infinity=0.5 The reason we get this is that there are many different ways to define infinity.
  2. I have had a physics professor that had unconventional ideas about relativity. He considered time dilation more as a slowing of clocks than a change in the flow of time. He has shown that time dilation can be considered to be the slowing down of clocks as a result of the mass change of the object http://www.newtonphysics.on.ca/kinetic/length.html . For example, as an object moves at close to the speed of light, it's mass is different, and so is the mass of the electrons in the object. This increased mass of the electrons would make the electrons move closer to the centre of their atoms and also move more slowly (this is the calculation of the Bohr radius). Any clock that is based on the motion of electrons (and all clocks are) would be slowed down in the same way. In his opinion this explains both the length contraction and time dilation. As far as I know there is no current experimental way of distinguishing the results of this theory, however I find this explanation more rational than the conventional theories which although accurately model the situation don't explaining things very well.
  3. I enjoy reading about how ancient cultures that used astrology in ways that science eventually found legitimate. Most of the legitimate application of astrology involved looking at the stars to determine the time of the year, which would be used to determine the best time to plant seeds or harvest. I suspect that these early successes of astrology encouraged the astronomers to make predictions that we now know has nothing to do with the positions of the stars.
  4. A Wheatstone bridge is a particular combination of resistors. Try wikipedia for more details. http://en.wikipedia.org/wiki/Wheatstone_bridge
  5. I am not certain which force you are trying to calculate. The Force that the rotating object will have on the post will be equal to the force required to keep that object rotating. F=mrw^2, where F is the force in Newtons, m is the mass in kg, r is the radius of rotation of the object in meters and w is the angular velocity in radians/second. This will apply if the size of the rotating object is small compared to r. If it is not, then give a good description of the object rotating. This will be the force where the rotating object meets the axis of rotation. If you want to calculate the force that this would have in the ground, you will need to consider the leverage that your design will give you.
  6. Particles are the smallest things that have been observed. Some particles like the electrons, muons, and neutrinos are considered elementary (not made up of smaller particles). Other particles like the proton, neutron and others are thought to be made up of quarks. No quarks have been observed in isolation, but their existence is expected. Even more theoretical is the concept of vibrating strings. The main concept behind string theory is that the everything is made of vibrating strings of some kind.
  7. If you require a precise answer then it will be difficult The first effect is that sound spreads out as it moves away from the source The other cause for attenuation is absorption which will be more important in materials. In matter, I suppose that the absorption of sound waves will decay exponentially with distance. The spreading out of the wave: The reduction in intensity due to this effect is I=P/A , where I=sound intensity, P=power of the source of sound, A=area over which the sound is spread over. The intensity of sound can be measured in watts per square meter. The threshold of hearing is about 10^-12 W/m^2, whispering is at 10^-10 W/m^2 and a rock concert may be 0.1W/m ^2. If you are in a wide open space, then you the area you will use is the area of a sphere with a radius equal to the distance between you and the source. A=(4/3) pi r^3 It would be difficult to calculate the attenuation of sound with distance in buildings because sound can reflect of walls and be channeled down hallways. Depending on what you're trying to calculate, it might be important to know that the ear's sensitivity to sound intensity varies with sound intensity. When comparing perceived sound intensities, you should express the intensity in decibels where: Intensity in db= (10dB) Log(I/10^-12W/m^2)
  8. Interesting article. I can see where you may have been confused by the article. Both gravity and matter can affect the propagation of light. The effect of gravity on light: A black hole can change the direction of light (deflection of any angle) but this will be without changing its speed. The photon will gain energy as it moves towards a black hole (blue shift) or it will lose energy if it is moving away from a black hole (red shift). However for light near a black hole the speed of light is constant. Slowing down light in a medium When people say that the speed of light is lower in matter, the mean that the distance traveled over the time interval is lower. What is happening is that as the light passes though matter, it gets absorbed then re-emitted after a short delay. This occurs multiple times. As it travels from one atom to the next it is traveling at the speed of light, but because of all the delays, it has a lower average speed . The subject of the article involves strange effect that occur when a liquid is flowing faster than the (average) speed of light that liquid.
  9. If something is moving at a constant velocity then the sum of all the forces acting on it will be zero. If something collides with your body, the object won't stay at the same velocity in this situation. The object will slow down (thus have an acceleration). The magnitude of the force will be equal to the product of the mass of the object and its acceleration.
  10. The question is not that complicated. The tension is how much force that the rope is applying to the system. Therefore, in this case, the tension is equal to P.
  11. Ok I see what you're saying now. ( I initially took your post as a joke, sorry about that) In curved space, a curved diameter will be longer than a straight diameter in flat space. So depending on the radius of curvature of space, the ratio of the circumference to the curved diameter will be somewhere between 2 and our currently accepted value for pi.
  12. More evidence of a variable value for pi The value of pi is clearly increasing with time. In biblical times, the value of pi was 3. If the circumference was 30 cubits and the diameter was 10 cubits, then pi was 3.
  13. Your answer would have been valid if the question did not specify that the graph must be shifted to the left. However since it does specify this, they are looking for the first value of t0 that is positive. You will find that "40 cos(100pi t +2pi)" is equivalent to "40 cos(100pi t)" because it is shifted by one full period. You can always add one (or multiple) period(s) to get a phase factor with the correct sign.
  14. No. There are many examples of good insulators with a low heat capacity. For example, many thermos bottles have a vacuum layer which would have a very low heat capacity but provides excellent insulation. A good insulator will have a low thermal conductivity which is different than the heat capacity. The heat capacity is a measure of how much heat an object can absorb, while the thermal conductivity is a measure of how much heat an object can transmit through itself.
  15. I assume that you mean how do you calculate mechanical work. If you apply a force to move an object then the work done will be the product of the force and the displacement of the object. W=Fd (if F and d are in the same direction. It can be more complicated if the force and displacement are in different directions, in which case: W=Fd cos(theta) where theta is the angle between the force and the displacement.
  16. This equation gives you the position as a function of time assuming a constant acceleration. In the equation v is the initial velocity. If the acceleration is not zero then the velocity will not be constant. If the acceleration is zero (a=0) then the equation becomes that of an object moving at a constant velocity.
  17. Nothing will happen. The photon will continue on its way, as if the field wasn't there.
  18. Here are the movies that I analysed to conclude that the amplitude does not change. I only did a quick analysis, Shortly after posting my last comments I found the relation between tension and energy but the equation also includes a velocity term I suspect may also depend on the tension. I intended on looking into it but other projects have been keeping me busy. http://www.geocities.com/marc.spooner/spring1.avi http://www.geocities.com/marc.spooner/spring2.avi For a sence of scale: the slinky has a diameter of about 6 cm.
  19. Experimental Results I have just done a quick experiment to test what the amplitude will be. The experiment consists of attaching three slinkies together, with one going to the left and two going to the right (almost parallel to each other ie this orientation: --======= ). I then made identical pulses along the two slinkies and filmed the wave as it reached the single slinky. Results: The amplitude transmitted to the single slinky is the same as that of each of the individual waves that made it up. So if two waves each with an amplitude A combine at the single slinky, the resulting amplitude is A and NOT 2A as expected by the superposition priciple. Explanation If you are using the superposition priciple, you are assuming that the medium is not changed as the waves meet. However in this case, the tension in the single slinky is twice that in each slinky of the pair. The energy of the wave is proportional to the tension in the rope and the square of the amplitude. So if the available energy doubles and the tension doubles, the amplitude must be unchanged. I have to admit that there was a fair bit of friction in this setup which may have reduced the resulting amplitude a bit.
  20. After thinking about it for a while I am not convinced that for a y-shaped string, the resulting wave would be a superposition of the the two original waves. The reason for this is that there would be a change in the tension in the ropes. If two strings meet and continue as one, then the tension in the one string will be twice that of the individual strings. The amplitude of the oscillation in the rope will depend on both the vibrational energy and the tension in the rope. (you can see this on a guitar string while you tune it) I intend to confirm this by monday.
  21. If you add two identical waves then the resulting wave will interfere constructively everywhere and will have twice the energy as two separate waves. If you have two waves with distinct sources, then it is impossible to combine them constructively everywhere. To produce two waves that overlap perfectly, then you will need have the source of the second wave will located on the first. Because the source of the second wave is interacting with the first wave, it will be harder to generate the second wave. Think about it like the stretching of a spring. More energy is required to stretch it from 1 cm to 2cm than was required to stretch it from 0 to 1cm (the energy of a spring is given by E=1/2 k x^2 ).
  22. If two identical waves interfere constructively with each other at a particular location, you will get twice amplitude and four times the energy at that spot. However it is impossible to add two distinct waves in such a way that constructive interference occurs everywhere. Destructive interference will happen somewhere and the total amount of energy is conserved.
  23. The actual answer will depend on the shape of the asteroid and it will take at least a page of algebra to get the answer your looking for, but i'll give a quick summary of the method you should use. The first step in calculating this is finding what the centre of mass will do. This is done by using the concept of conservation of momentum. Sounds like you will have no trouble with that. The second part of the problem is to calculate the rotation around this centre of mass. It will involve calculating the moment of inertia of the asteroid (see first year university textbooks for this). you will also need to calculate the total initial angular momentum of both the asteroid and the ship. Then you after they stick they will have a different moment of inertia but the total angular momentum will be conserved. This will not give you the answer in terms of x and y. For that you will then have to apply sine and cosine functions. I hope this helps you get started.
  24. Interesting idea. I've tried to think of how to experimentally test your speculation with the accepted theory. I'm convinced that both models predict that the force of gravity would vary as the 1/distance squared The main difference sems to be that in your model of gravity that if mass blocked this radation, then the force of gravity would depend on mass in a different way. Instead of being proportional to the mass the amount of radiation blocked by the mass would follow a exponential decay relationship. In reality, the force of gravity is proportional to mass F=GM1M2/d^2.
  25. The way to determine the answers to your question is to do a simulation applying the laws of gravity to a many body system. I have found the results of one of these simulations on http://www.sunorbit.net/ . Instead of just taking this data from the internet, if I were you I would either find or write a program to calculate the effect of the planets gravity on the sun. However from the results listed on the site I refered mentions that: 1)The distance between the sun and the centre of mass of the solar system is about 3 million Km (a few solar diameters). 2) The motion is not circular and described in the reference. 3) The period of this motion is 22 years. 4) The reference doesn't mention any results on Mercury's orbit. I suggest that you find out how to simulate the effect of gravity on a many body system. Only then will you have your answer. There are several simulations available if you google gravity and simulation.
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