Something to think about instead of working

[reggiegsd]

Wow, I had no idea there was this much pent up curiosity among the members.

The bullet question is actually the study of ballistics, or, how does a bullet move through the air. If you shoot a bullet absolutely level with no positive or negative elevation, it will shoot out straight and start to fall due to the effects of gravity.

If you hold a second bullet at the end of the barrel and release it at exactly the same instance as the shot, what will happen? Since gravity effects all things the same (at least at the masses we are talking about), the shot bullet will fall at exactly the same rate as a bullet that was simply dropped. Disregarding all other external influences, such as wind speed and direction, air pressure, the curvature of the earth, or the as yet unproven existence of Tino’s Mom, both bullets will hit the ground at the same time.

In Naval artillery, where you are shooting a “bullet” twenty miles or more, all of the above items must be taken into account, as well as the elevation of the gun barrel, the curvature of the earth, and even the earth’s rotation (this is called the Coriollis Effect). The first real computer, the Univac, was invented in WWII to calculate ballistic charts for artillery. The charts would allow the gun captain to quickly make his calculations and just maybe hit his target.

School is over, everyone go out and play.

[DAEDALUS]

The bullet will leave the barrel. It is travelling 1800fps relative to the gun...its just at a standstill relative to the person standing at the side of the road.

[toki]

First things first: Daedalus, you are smart. Almost as smart as me. :P

Second: The question is moot. What if all the birds were stupid and flew up and hit the roof of the truck at the same time, exerting say 3 newtons of force a piece, that's probably about 3000 newtons, seeing as canaries probably weight 1lb a piece, the truck could register lighter than it actually is. The situation provides for more than one answer, and so it's moot.

[toki]

P.S. If you are traveling at the speed of light and you turn on your headlights, what happens?

HAHA an oldie but goodie.

[szh]

If you all have this much time on your hands, you need to do a Google search and read up about Schrodinger's cat.

Here is a book on this fun topic:

http://www.amazon.com/exec/obi...lance

Z

[Simmsled]

Here is a brain buster.....if you were in a space ship (ie. flying saucer) going the speed of light would you break the speed of light (supposedly a feat not attainable) if you walked from the back to the front of the space ship?

[SmithSR]

If you were driving at the speed of light at night on a dark road, would your headlights light the road in front of you?

If you drop a penny from the observation deck of the empire state building, it will hit the ground with enough force to imbed itself in a sidewalk. What speed does a penny fall at to be able to drive itself into concrete? lol, freshman physics is cool.

If an airplane accelerates to three times the speed of sound, then slows down and lands, how many "sonic booms" will be generated by the plane?

[toki]

I am not a physicist or anything, but they have recently proven that gravity travels at the speed of light, and I dont know if gravity is a collective entity or if it is created per say, but it may accelerate to the speed of light when it is created, disproving Newtons little theory.

[forecast]

Regarding the original bird question,

daedlus is right, it's a fluid dynamics question.

A sealed crate full of birds weighs the same no matter the birds do.

A mesh crate with birds flying? It weighs more than an empty crate but less than if the birds all are on the bottom.

To see why, imagine a pasta drainer on a scale. Does it weigh a whole lot more when you pour water into it? Sort of, but it depends on how much water, the size of the holes and where the water is addes (at the edge or side).

The bird's wing effectively makes the air under it more dense than average, creating a downdraft. That downdraft will be dispersed christmas tree style and some will leak out the side of the mesh, some will hit the floor of the crate.

Yes, when a 747 flies overhead the ambient PSI of the air is raised slightly, the atmosphere has become 100,000 lbs more dense. Since the total weight of the atmosphere above you already masses 14 lbs for evey square inch, the increase is neglible. The effect also spreads out, like pouring water into a lake.

[forecast]

Here is a brain buster.....if you were in a space ship (ie. flying saucer) going the speed of light would you break the speed of light (supposedly a feat not attainable) if you walked from the back to the front of the space ship?

The ship can't attain lightspeed. It's not that going faster than light is impossible, but even going as fast as light is impossible.

Assume your ships traveling at 99.999999% the speed of light. Your mass is huge, acclerating in any direction requires tremedous force. Of course everything from sub-atomic particles up moves more slowly, so time slows down for the ship and people in it, thus your body can still move you about.

Suddenly! you break into run, moving forwards, the faster you move, the slower time gets and slower you acclerate. You never reach the speed of light since you heavier and heavier and soon have more mass than the entire galaxy, but time is going so slowly. By the time you reach the front of the cabin stars have been born and novaed.

[forecast]

Why in the forum where users currently browsing this forum are listed is your name always last?

[forecast]

ACTUALLY, the bullet would never leave the barrel of the gun.

The gun is traveling "backwards" at 1800 fps (with the car). The bullet ordinarily would exit the barrel at 1800 fps also. These two speeds would effectively cancel each other out, thereby leaving no force to act upon the projectile.

The mistake here is forgetting that when one object acts on another only their relative velocitie's matter. So to the gun, the bullet is standing still just before it is fired, no matter what is happening to the gun.

Keep in mind the earth is spinning, you travel 12,000 miles every day - 1000 miles a hour, faster than the speed of sound. But the earth is also moving. 1 AU * pi every year, many many times faster than the speed of bullet. And the sun is moving! and the galaxy too!

Your speed in relation to the average atom in the universe is quite large (no where need the speed of light, but still 1000's of miles per hour) but all that matters to is the speed of your Q when you hit that brick wall!

The bullet leaves the gun, very fast relative to the gun, not so fast relative to the guy on the ground.

[forecast]

P.S. If you are traveling at the speed of light and you turn on your headlights, what happens?

HAHA an oldie but goodie.

You can't move at the speed of light, but if you were very very very close, photons would still leave your headlights at the speed of light. The time dialation effects would make it seem as though the light was illuminating the road normally, they would travel down and bounce back off a rock, the return light would always hit the front of the car, before the car hit the rock.

Of course with the time dialation effect, the rock would be dust and billions of miles behind before your brain could process what you saw.

[aznromeox]

HEres one smarty's

I've always just thought of this.

Hypothetically speaking if we were able to travel faster than the speed of light *energy* 186,000 Miles per second. or 300,000 kilometers per second for you canadians ;-D, would our equiptment be too slow for us because we travel at the speed its moving. :-D

This is just a star trek thing i wonder. I'm not using any logic though. I know that weird stuff is suppose to happen if we were able to achieve this.

[forecast]

Pulled in a gas station lately and seen this sticker on the pump: "volume corrected to 25 degrees celcius"?

Is this a net good or bad thing for drivers?

[toki]

I've never bought into the whole not able to travel at the speed of light thing. It was impossible to go faster than the speed of sound at one point too. We all see how that turned out. Newtons little theory doesn't impress me, light acts as a particle and a wave, and therefor has a mass, being as it is a particle, and it accelerates to the speed of light, so to me that kind of negates his little idea.

[szh]

light acts as a particle and a wave, and therefor has a mass, being as it is a particle, and it accelerates to the speed of light, so to me that kind of negates his little idea.

Uh, no. Current theory is that photons (the light particles) have zero mass (of course, there are theories that photons had mass at the big bang). Einstein's Special Theory of Relativity requires photons to be massless. See:

http://www.signaldisplay.com/relativity.html

for the details.

This masslessness is, of course, being verified experimentally as well. Last time anyone reported looking, an upper limit of 10 raised to -51 grams was set - so, zero mass is still not experimentally proven, but it is an awfully good assumption. See:

http://www.aip.org/enews/physn....htmlh ... ra...b.htm

for more details. As for the interesting theory about photon mass at the creation of the universe, see:

http://focus.aps.org/story/v10/st9http: ... /s...19b1f

Photons do not "accelerate" - light always travels at a maximum velocity for the medium it is in. Vacuum is, of course, fastest and they slow down in other transparent media.

Z

[DAEDALUS]

It's accepted that Newtonian physics and quantum physics do not agree. I think in many cases Newtonian physics is really a subset of quantum physics, in which many factors and variables cancel out or are so negligible that F=ma is good enough for most applications.

Forecast, my shot-in-the-twilight guess is that the station applies a multiple to the volume pumped to account for the fact that gasoline expands and contracts with changing temperatures. As long as they do it correctly it's a fair practice IMO. I doubt it makes much of a difference though, or everyone would be doing it. Or maybe everyone already does?

[forecast]

Forecast, my shot-in-the-twilight guess is that the station applies a multiple to the volume pumped to account for the fact that gasoline expands and contracts with changing temperatures. As long as they do it correctly it's a fair practice IMO. I doubt it makes much of a difference though, or everyone would be doing it. Or maybe everyone already does?

I think is a clever way to sell fuel by weight rather than volume. I think most stations in cold climates do this. Seems the delivery trucks started a few years back selling it this way to stations.

Still it's kind of a puzzle. assume a 1% change in volume between 80 fer. and 40 fer. Who wins, the station or the consumer.

[Tino]

Yea well I can spit watermelon seeds farher than you :bshake

[DAEDALUS]

It's exactly a way to sell fuel by weight. I think the only reason we don't buy gas by the pound is because we've ALWAYS bought it by the gallon. Everything is geared toward volume from start to finish... even futures traders buy and sell crude oil contracts of 1,000s of barrels, not xxx tons. Its a global convention, not that we care what the rest of the world does <cough>meticsystem<cough>.

I think the question of fairness needs to be looked at from a different perspective. Since the chemical energy liberated by burning homogeneous gasoline is directly proportional to weight, and not volume, the practice guarantees you get what you pay for every single time. A station that doesn't normalize the price will profit less when its cold out and make more when its hot out. How do you take advantage of this? Go to the "correcting" stations when hot out (> 25C), and to the non-correcting stations when its cold out (<25C). This assumes they sell the gas for the same price. How much will you save across a 40-degree temp change at non-correcting stations? Assume you get 15 miles/gallon on gas at 40 degrees, and that you want to travel 300 miles somewhere and back again. You fill up at your destination, on gas sitting at 80 degrees. You will need 20 gallons on the way over, and 20.76 gallons for the trip back, so a 3.8% increase in cost. Simplified, roughly 1% for every 10 degrees.

[CaptainHenreh]

Here's one for you:

How does Commissioner Gordon call Batman if it's a clear night in Gotham City?

[DAEDALUS]

On the little red phone?

[aznromeox]

Here's one for you:

How does Commissioner Gordon call Batman if it's a clear night in Gotham City?

what, i don't understand your question..

[szh]

what, i don't understand your question..

The question relates to the fact that on a clear night, Commish Gordon can't use the Batsignal to shine a searchlight on the clouds (with a Batman outline in the searchlight beam).

Z

[szh]

On the little red phone?

I like this answer! Works in daylight too!

Z

[Get240DiZzY]

I've never bought into the whole not able to travel at the speed of light thing. It was impossible to go faster than the speed of sound at one point too. We all see how that turned out. Newtons little theory doesn't impress me, light acts as a particle and a wave, and therefor has a mass, being as it is a particle, and it accelerates to the speed of light, so to me that kind of negates his little idea.

Theoretically, it is possible, just not attainable.

Through my basic understanding of physics, I've gathered that the faster you go, the highter your mass gets. Once you reach light speed, you have an infinite mass, and to sustain your infinite mass you need an infinite amount of fuel for an infinate amount of time.

My favorite quote about this is, "traveling at the speed of light is to Humans as space travel is to an ameoba."

Physics is phun!

[DAEDALUS]

Sustaining speed isn't a problem. F=ma. To sustain any speed, a=0, so F=0, unless m is infinite. Then what? (Ah, there's that pesky Newton.) Getting there is the hard part.

[nissanrose]

LMAO at this thread!!! y'all are smart!! so if i need help with physics homework i'm going to one of y'all. i look at all this nwetons law crap and it blows my mind. i'm not good at math so i always failed this part of science class.

[toki]

Ok. If a particle of light has no mass, then to sustain light speed, it would have to have an infinite mass. But to have a mass in the first place to grow to infinate mass it couldn't accelerate to light speed. So uh. Back to the drawing boards? Quantum Leap light? jumps in to accelerate jumps back out to say "yo, i'm light?" And ofcoarse this is just sticking with Newton's theory.