Lsos

So basically, the sky is blue for the same reason that an orange is orange?

Gasoline has 32000000 joules in a liter. If you want something, a puck lets say, to go from 0 to 32000000 joules of kinetic energy, you're going to have to burn at least that liter. Not half of it. There's no other way around it (uness the energy comes from somewhere else). If there was, I'd be making a perpetual motion machine right now.

How do you get four times the energy out of twice the fuel? It doesn't add up mathematically. It has to be four times the fuel.

I don't think any mass gets made in this process...we end up with the same amount we started.

Just by accelerating something you are converting energy into mass, according to the theory of relativity. The faster something moves the higher its mass. Happens all the time in particle accelerators. I heard particles' masses can increase thousands of times in the most powerful accelerators.

I don't see why the rocket wouldn't take 4x the distance to stop. The same eqautions apply whether the force comes from the ground or propellant or gravity or anything. The same reasoning to why it would take 4x the distance to stop apply as well...it takes it only 2x the time to stop when travelling twice as fast, but since its average velocity is greater, it has to have travelled more than 2x the distance. 2x the velocity and 2x the time = 4x the distance.

All your ideas are good, but unfortunately there is a lot standing in the way. I thought about tidal power also, or harnessing all the energy that humans waste...but I guess we're not yet in enough trouble to go through with these costly methods. For example, I ran some simple calculations. Lets use the largest battleship ever built: the Yamato. A 10m tide comes in. Now, if we managed to extract ALL of the energy from this ship that has been raised 10m...it amounts to only about a 1/3ton of coal. Keep in mind that a coal power plant can burn 100tons of coal an hour. Keep in mind there's like 600 coal power plants in the US. To replace just what one generates in a day you'd have to build what...like 7000 tidal power-plants the size of the biggest battleship ever built? I'm sure as hell not going to put my money in that project. The methods you mention make sense...but once you get down to thinking about them they are just too extreme for right now. I mean, you're talking about salvaging every ounce of braking energy of a car, or even putting a generator on a treadmill, or hell, piezoelectric crystals in my running shoes....and yet as we speak, oil rigs are flaring off ridiculous amounts of natural gas, just because it's not worth keeping it. I'm sure we've all seen pictures. Basically, your ideas are extreme to put into practice, and we're just not at that stage yet. Hopefully we never will be...

Exactly. If by vacuum you mean "emptiness", or nothing, then yes, throughout the universe where there's nothing there's...well, nothing. However, there's always something. Even in "empty" space we'll find a particle here or there. Maybe every meter, maybe every mile. Closer to earth, you'll find many more. Hell even between atoms there's "empty" space. I suppose you could ask if that empty space equally distributed...but how do you really answer that question?

I don't know if this has been answered or pointed out already, as I just skimmed the thread. But, the fundamental flaw you're asking for is this: Assistance means you're adding energy into the system that you haven't accounted for. I can't even push a small car to 1 mph...even though it takes probably the same amount of force to get it up to 2 or 3 or maybe even 20mph. I'm sure if I had the assistance of another car then I could probably push the original car much faster. Even though my arms can only supply the same weak force, the assisting car is supplying the velocity, which in this case makes up most of the energy. Another thing, work cannot be Force x Time, because if it was then I would have done 784N x 8100seconds = 6350400joules of work sitting on my *** half asleep in my office because I partied until 3am last night. The fact is, no work has been done. None.

I see what he's saying with the direction of the fricional force. By definitions that I have seen, frictional force is supposed to oppose the tendency of motion....and yet in this example, it doesn't. It opposes the tendency of motion at a right angle. I understand that this is necessary for the car to turn and whatnot, but it seems to go against the definition. Could the definition be wrong?

I could never grasp that...how can radiation escape from a black hole if nothing, not even radiation, can escape...

All the energy probably does get wasted as heat. Still, I doubt you're expanding nearly as much energy merely pushing on something as you are when actual work is being done. Many times at the gym I was able to hold a weight in position for a couple seconds, but try as I would I could not get it to move.

I used to wonder the same thing myself.... Basically, you're only half right when you say it takes you four times longer to stop. Four times longer the distance, but not four times longer the time. It only takes twice as much time to stop something going twice as fast.... Lets say you try to stop from 10mph and it takes you one second. Now try to stop from 20mph and it takes you, as expected, 2 seconds...twice the time. But, don't forget that during those 2 seconds you were also going, on average, twice as fast. Twice the time AND twice the speed...and you've got 4x the distance. There's no black magic...it makes perfect sense if you think about it. Is this what you were looking for, or am I completely off?

Hello, I am Lsos. I've been looking over this site and it seems great for discussing and finding out about things that interest me. I hope to learn something, and maybe someone can learn something from me! Oh, and if someome is looking for a good party, let me know :hihi: