Q: As you approach the speed of light, what happens to mass.
Assuming you started with mass then will it increase as in Einstein's equation?
Correct
Q) Can you exist in two places at the same time? If so explain how it is possible.
Not entirely convinced by your previous suggestion!
In the example I used earlier until the person who knows I'm in one of either places where which would cause the wave function to collapse I would theoretically exist in two places using the Copenhagen interpretation, in what way do I only exist in one place from somebodies point of view who knows I am in one of two places with equal probability?
Q) Two suns of the same mass, one releases twice as much light intensity as the other, which sun releases the most energy?
Going back to mass/energy equivalence, I would expect them to be the same?
Correct
Q) If you can't see a black hole, how can you observe one?
Surely you can observe its impact on light sources behind it? I would guess the Hawking radiation(?) can also be measured.
Interesting idea but no. Theoretically Hawking radiation should allow for a black hole to be found but as far as I'm aware a black hole has yet to be found this way. A black hole would be observed by it's affect on surrounding matter (Light, planets, accretion disks). If a planet can be observed apparently orbitting nothing then it would be likely this was near a black hole and you could actually calculate the mass of the black hole
Q) Is pressure inversely proportinal or directly proportinal to temperature?
Directly?
Correct
Q)Why were cane toads introduced to Australia and why have they become a problem?
Weren't they introduced to get rid of another pest that was destroying a crop? Do cane toads have no predators?
Yes, the cane beetle that damaged cane sugar crop. They do have predators but these predators have no protection from the toxin ingested when eating a cane toad so any species that decides to predate on cane toads ends up having a dip in the population and cane toads can again flourish.
Q) Presuming we live in a flat universe (although evidence suggests we don't, a flat universe stops expanding but doesn't start accelerating back to the central point) What would happen if you were to go to the edge of the universe and then travel into what apprently doesn't exist yet
This makes my head hurt. If your rules of the game allow this to happen then you'll end up in another universe.
I don't know if this is correct but my theory would be you would create space/time as you travelled. Are you saying our universe is travelling into another universe? Our universe is currently expanding into nothing (which funnily enough can't exist theoretically but I'll use that term anyway) so if you think we would travel into another universe if we left the realms of this universe then you are implying that we are currently travelling into another universe which I 'm pretty sure wouldn't be possible
Q) Can you prove the existance of gravity?
Doesn't gravity describe an observable effect? Experiments can be repeated and measurements taken on this effect, so yes. As to the existence of a force acting over long distances, I would currently guess no.
Sort of a trick question, it depends on what you define proof as. As of yet we have no proof of a particle that gives things gravity but we have proof beyond reasonable doubt that gravity does exist. I dare say either yes or no is correct depending on your stance of proof.