Physics Questions

[sgtpepper]

2) THEORETICALLY (I know you'd disintegrate due to air friction and all that), if you are in an object traveling at 1 km slower than the speed of light, and you walk/run forwards, what happens? Are you ABLE to walk forwards? It's impossible to travel the speed of light, but is it relative to anything?

Reminds me of one of Steven Wright's jokes-

One time right in the middle of a job interview I took out a book and started reading. The guy said "What the hell are you doing?" Then I said, "Let me ask you one question. If you're in a vehicle and you're traveling at the speed of light, and you turn on the headlights, would they do anything?" He said, "I don't know." I said, "Forget it then, I want to work for you."

Comedic genius

[teraflop122]

If there is no center, how does EVERYTHING move away from EVERYTHING else?

Think of the 2 dimensional surface of a balloon as the 3 dimensions we can measure, and reread this:

Think of it like dots on a balloon, with the surface of the balloon being our universe and the dots as galaxies. When you blow the balloon up (simulating the expansion of the universe) the dots move farther away. Essentially, space (the membrane of the balloon/universe ) is being "stretched".

The universe does not have a center in three dimensions of space, however there is a center to whatever 4,5,6,7,8+ dimensional shape the universe is. As such you are never going to travel there or pinpoint it- There is no point X,Y,Z coordinate for the center of the universe, but perhaps an X,Y,Z,A or X,Y,Z,A,B.

[Gamelver]

Then I suppose the membrane is our 3D space, with the center of the balloon representing those hidden dimensions, possibly .

[timmeh87]

so far i think almost everyone here hasnt grasped one of the basic concepts of relativity - what relativity means

if you are travelling near the speed of light and turn on a light, how fast is the light going? the speed of light of course! no matter who you are, where you are, or how fast you are going, to YOU the speed of light is always the speed of light.

and why? because as you move faster time slows down. haha. have fun trying to figure that one out.

this should be required reading on this thread:
http://en.wikipedia.org/wiki/Speed_of_light#Physics

and that is mainly why you'll never get to the speed of light (that and the infinite energy thing)

[Black Six]

I encourage anyone here interested in this stuff to take a physics course that covers relativity. Do this and you'll see that while some of the questions posed do not have answers yet, others, like #1 and #2 have very simple answers (as have been posted by others). Remember people E = m * c^2.

[Krepticor]

1) we do not feel the velocity because of newtons laws F=ma where acceleartion is the change in velocity and the velocity never changing means no acc. therefore, no force

2) Approaching the speed of light was theroetically impossible, however, I think the theory is that is you cannot ACCELERATE to the speed of light, doesn't say you cannot move at it

3) The universe is ever expanding and I think the Center as you speak doesn't exist since the center never existed...think about it

4) The is NO MATTER in the universe so it can expand and contract all it wants, nothing is still nothing

[HomicidalBarber]

Inertia my dear boy!

[teraflop122]

1) we do not feel the velocity because of newtons laws F=ma where acceleartion is the change in velocity and the velocity never changing means no acc. therefore, no force

Acceleration is the change in velocity. Velocity is the speed And Direction. A change in speed, or a change in direction , is a change in velocity. Therefor you are always under acceleration when travelling in a circle, because your direction is always changing.

Come on, people, this isn't rocket science!...oh, wait

[bicostp]

I think it's because gravity is many times stronger than the revolving force. Picture a bolt stuck to a spinning magnet. The magnet holds the bolt "down", that is toward the center of its mass. If you marked and spun them you probably wouldn't see much movement.

The gravitational acceleration on Earth is about 10m/sec^2. (9.8 if you want to be picky.) At the equator, the centripetal acceleration is 0.006m/sec^2. The planet would have to be spinning a lot flaster for us to notice any movement. (Remember the further away from the equator you are the slower your revolutions are, since you have to cover less ground.)

This actually has a bit to do with the <a href="http://en.wikipedia.org/wiki/Coriolis_effect">Coriolis effect</a>, which causes hurricanes and winds to move in certain directions depending on location. The large air pockets and storms are just so massive that they are slightly affected by it, but anything smaller generally doesn't notice it very much. Pretty much the only people who are worried about it are meteorologists and soldiers firing artillery.

Basically, as far as our senses are concerned, gravity overwhelms the lateral acceleration.

Source:
http://www.newton.dep.anl.gov/askasci/p ... y05087.htm

[vskid]

The gravitational acceleration on Earth is about 10m/sec^2. (9.8 if you want to be picky.) At the equator, the centripetal acceleration is 0.006m/sec^2. The planet would have to be spinning a lot faster for us to notice any movement. (Remember the further away from the equator you are the slower your revolutions are, since you have to cover less ground.)

So going by that, you actually feel like you weigh more the further from the equator (I know it wouldn't be enough to "feel", but you'd have the same mass)?
And BTW bic, acceleration has one "l", you had two "l"s in all of them in your post.

[Triton]

im pretty sure mass is a constant, in space you dont weigh anything but your mass is the same, on jupiter you would weigh tons but still have the same mass, i think anyway

[vskid]

im pretty sure mass is a constant, in space you dont weigh anything but your mass is the same, on jupiter you would weigh tons but still have the same mass, i think anyway

Yeah, mass is constant. Kinda sounded like I said your mass would change, sorry.

[timmeh87]

you would feel heavier further from the equator if the earth was a smooth sphere.

But the value of the gravitation field is also dependent on the density of the rock in the crust, and the amount or rock that is there. The effect of this far outweighs any centrifugal force.

this is a map of earths gravity (red stronger)

<img src="http://www.gfz-potsdam.de/pb1/pg3/grim/grim5_fig3.gif">