Hi all, \n\nI need this answered fast, im doing my science hmwk and cant figure this one out .....thanks!
127355
because steel expands with heat (and contracts with cold) - so: if too hot, and rails were butted end-to-end, the rails would buckle with obvious BAD consequences! it is the joints that make the clickety-clack sound
453548
I understand your frustration in receiving no Answer yet to this question, but since I do not have any direct knowledge of how to perform the calculation(s) you need ... I hope the link below serves you well.  It appears to explain the mathematics behind all the concepts you mention.
393264
Here you go: http://www.gsfc.nasa.gov/scienceques2004/20041105.htm
118736
I have looked at so many websites trying to find this answer and I have not found anything. I will keep trying, but it seems to me that the answer is nowhere to be found. Sorry.
14894
Check out the sites below for in-depth explanations.  \nThe first one is from NASA.
625630
by any chance is this a question from your maths homework? lol :D\n\nI cant work it out myself because to put it simple, im crap at maths.
306669
It looked like the hover boards worked with some sort of magnet on the bottom that probably conteracted with the earth's magnetic force. Since, water isn't magnetic, the hoverboard wouldn't work on water. Thats what I thought at least.
28854
the earlier equation is not balanced.\nCaO + 2HCl --------> CaCl2 + H2O
647359
Look up stuff like Arrhenius equations. I don't have my phys chem text book to hand.\n\nFor part two, I think it's D, as I'm fairly certain it's not any of the others.
293080
Niuchemist is mostly right and deserves the vote, but there is one correction I would make-heavier molecules don't necessarily have less "kinetic energy", they move more slowly-it is the speed of movement that is the critical thing, not the kinetic energy, which is a product of speed *and* mass.
166268
The answer is Pressure\n\n10 pts plz! im only level 1!
52724
Hey asker, this is a great puzzle.  Could you provide the correct answer after a couple of days?  I am really curious.  Thanks.
491970
Someone posted the exact same set of questions a few days back, either here or on the physics page - you ought to be able to find the methods in the responses. Have a look.\n\n\nBest of Luck - Mike
183457
Here is the best answer...\nhttp://science.howstuffworks.com/steam1.htm
2621
here's a site with pics that might give you some ideas:\n\n\nhttp://www.physics.usyd.edu.au/competition/comp1998/comp98.html
501319
force of air is less than it's weight therefore it rises and it drops.\n\na=b
399144
Wow!!! dis brain teasers a nice one!!! and hey i wud like to know the answer to this!!!!