Jump to content

Endercreeper01

Senior Members
  • Posts

    840
  • Joined

  • Last visited

Everything posted by Endercreeper01

  1. It depends on if you are thinking of light as a wave or a particle. In a vacuum, as a wave, the wave is not a straight line, but as a particle, it would be straight. In a vacuum, there is nothing for it to interact with as a particle. As a particle, it wouldn't be like that because of special relativity. If the path was longer, then c would be greater then 299,792,458 m/s. This s not true because we have made measurements with special relativity and the Lorenz factor. If c was different, then the Lorenz factor would be different in the measurement, and therefore, special relativity (sing the value of c we have measured) would not be 100% accurate, and we would have to use a different c.
  2. When is the limit? And what about the brain?
  3. Is there a limit to how much our bodies can adapt? For example, if you lifted weights and you lifted more and more, will there be a time when your muscles can't get stronger?
  4. What if your gene had traces of disorders. Would you be happy?
  5. Yes, but wouldn't it be cruel to restrict people from reproducing based on their genetics?
  6. We could also set the value of D to the drag coefficient it would have if it was a cube with length 1 times the length of the object
  7. And also, we need to change D to the coefficient of drag it would have if it was a rectangular prism with that characteristic length, since D depends on Re and Re depends on characteristic length
  8. Does anyone have a good source for the drag coefficient of a flat plate depending on Reynolds number? I was unable to find a source that did.

    1. gwiyomi17
    2. Endercreeper01

      Endercreeper01

      IS there a graph?

       

    3. Endercreeper01

      Endercreeper01

      Update: Is there a graph for a cube of length 1?

  9. I would rather be intelligent because you can use intelligence to make you happy
  10. What do you think? Do you like my theory?
  11. 1. I know how to create graphs, but not how to put them on top of each other 2. It is likely that they are talking about the coefficient of form drag only 3. it gets changed because the average angle from the angle of attack is cos(90-a). This is because the angle of attack is measured parallel to the velocity, and the angle we use is measured perpendicular to the velocity. Therefore, we use cos(90-a). Because cos(90-x)=sin(x), we can rewrite it as sin(a) 4. I don't know how
  12. Yes, can you share some? I am trying to make a theory. I might try to publish it
  13. 1. I don't know how to plot them over each other 3. In this case, it is different. Cf0 is just the Cf it has with no angle of attack. The angle of attack effect goes to both terms because of the distributive property. This is why it is Cf0sin(a) 2. It must be roughly 0 because there is little intercept at a=180 4. Then it would be about 1.8. The method I used was fitting parameters and my theory. Because a is measured parallel instead of perpendicular to the velocity, it would be sin(a)
  14. Ok, I will show a plot. Let's go back to a previous plot. My theory predicts that Cf=Cf0sin(a) where a is the angle of attack. In this case, Cf0 is about 1.8 because the value of the function at 90 degrees is the form drag it has with no angle of attack, and the sin of 0 is 1, so then you get Cf0. Now, let's make a plot of this equation: Cf=1.8sin(a) The 2 graphs are exactly the same, except that the second one uses radiants.
  15. Why can't I post pictures?

  16. So, you want a plot of my equation? Or do you want me to present it in another way? I am confused about what exactly you want me to tell you.
  17. We don't sum over angles greater then 90, and you would take the limit as n--> infinity of the sum over n. Ok, I will show some graphs. This one is how the angle of attack a effects the drag coefficient: From http://www.aerospaceweb.org/question/airfoils/q0259c.shtml Pay attention to the wind tunnel part. There is an intercept, and that is the other effects of the drag. But, do you see what Cf is proportional to? It is proportional to sin(90-a) because the angle of attack is not relative to the axis perpendicular to the velocity, but parallel. The constant of proportionally is Cf0, or the coefficient of form drag it has when a=0. Another reason it is proportional to sin(90-a) is because at a=0, the sin(90-a)sin(90)=1, and so it becomes just Cf. It has to be proportional to a trigonometric function because you are dealing with angles, and it can't be cos a because if it were, it would get smaller instead of bigger. A 3rd reason is because the function appears to approach something. It appears to approach the constant of proportionality. Here is another graph from http://www.aerospaceweb.org/question/airfoils/q0150b.shtml for the angle of attack that uses the same equation: The equation for skin friction drag I can not take credit for because that is not what I came up with in my theory
  18. What do you want a graph of? Why should the average of the airfoil be that of a sphere?
  19. First, read them again. I explained it in my posts. Now, lets address how they correlate with data. I am assuming that they all have roughly the same skin friction drag and Reynolds numbers that are close to each other. Let's start with the cubes. The cube has a drag coefficient of 1.05 and the angled has a drag coefficient of .8. The average angle of the angled cube is 45 and it is 0 for the cube. Because Φavg=θavg for both cubes, it becomes just Dcosθavg. For the cube, the average angle is 0, and the cos of 0 is 1. Then, it reduces to D. The cos of 45 is roughly .7, and the answer is .735. It is close. The other factors would be the skin friction drag and the difference in D between them. For the cone, then it is different because we don't know what θavg is, and the same for the streamlined bodies. For the sphere and half sphere, they have close drag coefficients, and that is because of how Φavg affects the drag, or it could be because of the difference of D And also, there are a few ways to calculate an average. One way is to sum over all angles and divide by the number of angles.
  20. Because of time dilation, then time slows down the closer you are to the speed of light. This means that it will take less time for you to get there. There is also length contraction. The length contracts the faster you are to the speed of light. You multiply the original length or time by (1-v2/c2)1/2 to find the relative time or length. Because of this effect, if we get something to travel close to the speed of light, then time and length will greatly shrink, making it take less time to get there.
  21. 1. I meant minus 2. I did show how they were derived Do you actually read the whole post? 3. This is for the coefficient of drag
  22. There is also the drag from the wind If you have a wind speed of vw and an initial velocity of v0, then the total velocity is v=(vw2+v02)1/2
  23. Do you ever feel ignored?

    1. pears

      pears

      Psst no-one answer him - only joking ;P

    2. Iota

      Iota

      Only when I'm being ignored

    3. WWLabRat

      WWLabRat

      I'm sorry, did you say something?

  24. Provide real evidence, and maybe we will believe you
  25. We could use relativity to be able to travel large distances
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.