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Another problem:I saw this on "MYTHBUSTERS"
You drop a bullet from a certain height and measure the time it took to hit the ground then you shoot the bullet with a gun perfectly horizontal at the same height which one will take longer to hit the ground?
Simple, they both hit at the same time.
 

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Discussion Starter #22
Yep Dave , thats what they say.
I just came up with another problem
You shoot a powerful gun PERFECTLY VERTICAL Which will take longer for the bullet, the way up or down? What about if you do the same in vacuum.
I have an answer but not sure it is correct. There is an element of this problem that most will forget to consider.
Dont forget we need two answers: in air and in vacuum
 

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I think the bullet would go up faster then down in atmosphere and down faster than up in a vacuum, but. In a vacuum it would also travel up faster and farther so it might not matter.
 

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For the first part with the possible exception your old Daisy BB gun the terminal velocity will be less than the muzzle velocity so longer down than up.

For the second part acceleration down will equal deceleration up so the time will be the same.
 

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Simple, they both hit at the same time.
It depends. Is there a variation in local terrain so that the bullet hits a hillside before it would reach the ground if the local terrain were flat?

Is the starting height large enough that the curvature of the Earth will have an effect? How far does the bullet travel before reaching the ground?
 

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It depends. Is there a variation in local terrain so that the bullet hits a hillside before it would reach the ground if the local terrain were flat?

Is the starting height large enough that the curvature of the Earth will have an effect? How far does the bullet travel before reaching the ground?
No, the premise is the bullet is fired perfectly level over a flat surface. The bullet travels as far as it can go in the time it takes to drop the distance from the muzzle to the ground. For instance, if the distance from the ground is far enough to take 1 second to drop and the velocity is 1000 feet per second it would travel 1000 feet before hitting the ground.
 

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No, the premise is the bullet is fired perfectly level over a flat surface. The bullet travels as far as it can go in the time it takes to drop the distance from the muzzle to the ground. For instance, if the distance from the ground is far enough to take 1 second to drop and the velocity is 1000 feet per second it would travel 1000 feet before hitting the ground.
Dave,

I will agree that the premise is flat ground but the original post did not clearly state that.
 

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Discussion Starter #28
Another questionable thing is if we see the colors alike. When I was a kid my mother told me a certain color was red. Regardless how I saw it she called it red.
Then another kid was seeing a color totally different than I did . His mother told him the color was red.
As grownups we both agree that the color we are seeing is red but we might see totally different colors.
Is there any proof we see the same color looking at an object?
 

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Another questionable thing is if we see the colors alike. When I was a kid my mother told me a certain color was red. Regardless how I saw it she called it red.
Then another kid was seeing a color totally different than I did . His mother told him the color was red.
As grownups we both agree that the color we are seeing is red but we might see totally different colors.
Is there any proof we see the same color looking at an object?
Peter,

There is science that can measure the wavelength of light that is emitted by an object so you can prove that the light entering the eye from the object is the same wavelength.

There is no way to measure the reaction of the rods and cones in the eye when the light strikes them. There is no way to measure the reaction of the brain to the signals from the eye.

There are no methods for humans to directly share experiences (such as the famous Vulcan mind meld).

So there is no proof that light creates the same experience in different people. Given that some people are color blind (most noticeably Red-Green) it is obvious that not all people see the same color when looking at an object.

The question hinges on definition of the word "see".

This is very similar to the old question: If a tree falls in the forest and no one is there to hear it, does it make a sound?

The answer depends on the definition of sound. Is sound the vibrations in the air or the perceptions caused when the vibrations impact the human ear?
 

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Another questionable thing is if we see the colors alike. When I was a kid my mother told me a certain color was red. Regardless how I saw it she called it red.
Then another kid was seeing a color totally different than I did . His mother told him the color was red.
As grownups we both agree that the color we are seeing is red but we might see totally different colors.
Is there any proof we see the same color looking at an object?
I have pondered that question myself. My son is color blind so I am curious. If he is told an object is red then whatever color he is seeing should to him be called red in my thinking but is it? He can't tell me because he doesn't know either.
 

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If he is color blind then he sees everything in shades of grey, that's what my cousin tells me as he can't see color. When he 1st saw my 1500 he asked me what color it was. I looked at him funny and he said he was serious, that he was colorblind and could not tell. I didn't know that about him until then.
 

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That's not how most colorblindness works. I can see blue, but purple evades me, for the most part, and I can see some greens but others simply don't show to me. What I see when I look at a color is pretty different from a person with good color vision, but not in the ways most people think.

Green and brown mostly look the same to me. So do pink and gray, and as said above, blue & purple. A green traffic light looks white and I can't tell the difference between the orange and red lights. Cataracts and age seem to be making it worse.

Stigmas are getting better but when I was a kid I had teachers punish me for not learning colors in art class. I could see some colors, so they figured I couldn't be colorblind.

Now there are glasses that they claim can compensate.
 

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If he is color blind then he sees everything in shades of grey, that's what my cousin tells me as he can't see color. When he 1st saw my 1500 he asked me what color it was. I looked at him funny and he said he was serious, that he was colorblind and could not tell. I didn't know that about him until then.
No, just some colors are different. When he was small we were driving behind a road grader with flashing amber lights and he asked what those green lights were for. That's when I first knew he was color blind. There are probably different kinds of color blindness.
 

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big PIA
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I could have misunderstood how he said it, maybe it was just some that were that way, we only talked for a couple minutes and it was over a year ago. Sorry about getting it wrong, we did not discuss it for more than a minute and I wasn't really paying close attention and may just remember exactly the way he told me wrong, sorry.
 

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I am pastel color blind, I usually can't see the little green numbers in a color chart, hidden amongst the pink colored dots.


I see shades of green, and I see shades of red, and shades of blue, but my rendition of purple is not quite the same as what my daughter says "is purple" :)


I passed the FAA pilot's test in that I can see Green enough to know it is not RED, and White is pretty much white.... Amber tail lights are not good for me, but I can tell they are a faded out looking yellow.
 

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I see shades of green, and I see shades of red, and shades of blue, but my rendition of purple is not quite the same as what my daughter says "is purple" :)
Soooo, what color do you think your signature is?
 

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Discussion Starter #38
This problem I have heard long ago in the old country. The guy asking it asking it also provided the answer. I didn't bother to check it till yesterday. To me the answer is surprising

Here it is:
We assume the perimeter of the Earth at Equator is EXACTLY 26K miles and the Earth is perfectly round.
Someone that has nothing to do and a long rope;instead of hanging himself decides to run this rope along the Equator for a complete circle.
Later he decides to lift the rope one foot of the ground all around the Earth ( he is really nuts)
How much extra rope does he need for the rope to be continuous?
Are we talking feet, hundreds of feet, miles or more? Please provide a guestimate without computation
 
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