If you had a spaceship travleing at half the speed of light then shot a bulit at half the speed of light again, would the bulit appear to go the speed of light relative to an outside obverver?
(All preposed in theory, of cource.)
Hi, doesn't the gravity of a black hole remain relatively the same? It should because gravitational attraction depends on mass, which stays the same. And if it does, is it posible for a planet to orbit the BH.? (without light, of course)
Does't it seam odd that we have to use energy to cause something to loes energy. In a freezer you compress the gas (energy expended) to cool and de compress, so as to cool your fridge. Isn't there a way to cool somthing without useing energy (short of sending it to the antarctic).
I really enjoy building model rockets, however, I moved oversees and can't get premade engins. Nor can I get potassium nitrate or any other common combustable.
What can I do to make a small solid rocket engin??
This is just something I was thinking about...
would it be better to design a scuba flipper that has only one up and one down stoke for every cycle instead of the scissor kick? If so (or not) what would be the advantages and disadvantages?