Science & Mathematics - 12 December 2007

Chemistry Problem: (I just cant solve it)

What is the minimum speed at which a 1 kg snowball is thrown at a wall so that it will vaporize on impact? Assume frictionless, no speed loss or gain, etc.

My chemistry teacher said it had something to do with the specific heat of Ice, but I cannot solve it.

2007-12-12 14:48:43 · 1 answers · asked by J PAO 1 in Chemistry

2007-12-12 14:43:45 · 1 answers · asked by alexandervk 1 in Physics

The earth (mass= 5.98 x 20^24 kg) orbits around the sun (mass= 1.99 x 10^30) at an average distance of 1.50 x 10^1 m. What force does the earth exert on the sun?

a. 5.29 x 10^33 N
b. 5.28 x 10^32 N
c. 3.53 x 10^22 N
d. 8.85 x 10^8 N

please explain thoroughly how to do this problem.. please.

2007-12-12 14:41:55 · 1 answers · asked by Anonymous in Physics

Can anybody list out some forums that have a lot of expects with the ability to identify the name of plants?
I want to seek help from expects to help me identify these plants:
http://www.geocities.com/zfc89/plants.html
I have tried yahoo answer before, but can't get a best answer. The worst thing is, my questions is removed and my point is downed!

2007-12-12 14:38:24 · 3 answers · asked by Anonymous in Botany

I'm reading a book called A short history of nearly everything by Bill Bryson, and all these things, Quasar, blackhole, singularity, fascinate me. Yet, I have no idea what they are.
Could you please explain these to me, their theories and their relationship with each other? what's a blackhole got to do with quasar... etc Thanks

2007-12-12 14:30:15 · 7 answers · asked by ara_sweetipie 1 in Astronomy & Space

We had a meeting at work today with a little demonstration by the president. he divided us into two teams of 10, 5 facing 5, and instructed us to simply lower a bar of steel to the floor; the only "customer requirement" was at no time was anyone's fingers to not touch the bar.
the outcome: the bar of steel kept going up instead of down, no matter how much crabbing and complaining to each other ("why are you raising instead of lowering!!" and "down, not up you idiots!")
can this be done? or because everyone is so intent on keeping their fingers on the bar, it will never go down, only up??

2007-12-12 14:28:54 · 3 answers · asked by nascarmommy 4 in Engineering

ok i think it's a compound but i don't know.... i know that the amount of gold used in jewelry is made from like 10 to 22 karats?


help me out

2007-12-12 14:19:54 · 8 answers · asked by katiebug 2 in Chemistry

hey just out of curiosity... can solar powers b made out of plastic?

2007-12-12 14:18:56 · 3 answers · asked by Ana Banana Fofana ... ANA 2 in Other - Science

2007-12-12 14:17:49 · 3 answers · asked by rogerman 1 in Engineering

I have to do a report in science on Molybdenum, does anyone know anything about it? Any experts on the elements? Websites on Molybdenum aren't very helpful, so, please help, it's due in two days.

2007-12-12 14:14:15 · 1 answers · asked by Tiki Tiki 2 in Chemistry

2007-12-12 14:12:36 · 2 answers · asked by Tarot 4 in Biology

Calculate the hydronium ion concentration and pH of the the solution that results when 22.0mL of 0.15M acetic acid is mixed with 22.0mL 0.15M NaOH.

2007-12-12 14:12:20 · 2 answers · asked by Anonymous in Chemistry

Is it possible for two objects with the same mass to have different rotational inertias?

_____ Yes, if the two objects of the same mass are rotating with different angular velocities then they will have different rotational inertias.

_____Yes, if the same mass is distributed at different distances from the axis of rotation in the two cases.

_____No, two objects with the same mass will always have the same rotational inertia because only the total mass not the distribution of mass determines the rotational inertia.

There may be more than one answer.

2007-12-12 14:08:25 · 3 answers · asked by shamsan_415 1 in Physics

In order to determine her pulse rate,June's nurse counted 18 beats in her pulse in 15 seconds.At this rate ,how many beats would she have in 60 seconds? _________=__________

2007-12-12 14:00:45 · 3 answers · asked by nadie einzzz 1 in Medicine

Piezoelectricity is the property of some crystals to output electricty when put under mechanical stress.

Does anyone have any ideas about what your could use the electricty from this for???

2007-12-12 13:56:16 · 5 answers · asked by gabriel_d_popuch 1 in Physics

was it a piece of paper? was there a logo like Rx like you see these days? how did doctors give information to drugists?

2007-12-12 13:56:16 · 3 answers · asked by Westsail43 2 in Medicine

How many of each tiles are there?

My son had a total melt down with this question. I tried and tried to explain and here was my explanation...however was I correct?
600 divided by 2 is 300
so 300 plus 80 is 380 square tiles
so 300 minus 80 is 220 triangular tiles
total tiles is 600
Did I show him correctly?

2007-12-12 13:56:05 · 6 answers · asked by OMGiamgoingNUTS 5 in Mathematics

how do we sense smell? when will we evolve to sense other dimensions? what is it about the brain that stores memory and can creat out of nothing or wonder? how can we use 100% efficiency in gas engines or electric enginges? Is white a color? do you think we can benifit or even one day having downloads into the brain or sharing memory so that at age 2 you know calculus? when will other life decide to talk to us? out of the whole space there has to be other worlds fit for liefe. there is.
space is infinite which means that there is life theres an infinite chance of it.
of you can travel the speed of light time slows down so if you travel fast enough can you slow time to a negative speed thus traveling back in time?
how can we utilize other forms of energy? food can bbe used to power a light bulb but its nto efficient enough per food amount. the answer to any of these questions is greatly aappreciated. thank you.
and why was there matter at all? where did matter come from...............

2007-12-12 13:55:49 · 3 answers · asked by Kai 2 in Physics

2007-12-12 13:55:09 · 38 answers · asked by beachblondie 1 in Mathematics

How many grams of KCl (molar mass = 74.55 g) will be produced from the reaction of 50 mL of .3 M KOH with axcess HCl?
KOH(aq) + HCl(aq) --> KCl(aq) + H2O (l)
1. 9.31 g
2. 1.12 g
3. .876 g
4. 4.65 g
5. 6.98 g

2007-12-12 13:52:56 · 4 answers · asked by Anonymous in Chemistry

The ability of vacuum is to suck and there is no atmosphere of moon. So why are the lunar surface materials not suck by the vacuum?

2007-12-12 13:52:18 · 19 answers · asked by ? 3 in Astronomy & Space

F(x)=sqrt(x) a=1
My prof put (1/2)(x+1) as the answer, but I did not get that.
I used
F(a)+F'(a)(x-a)
1+(1/2)(x-1)
1+(1/2)x-(1/2)
(1/2)x+(1/2) is what I got. Am i doing something wrong?

2007-12-12 13:48:45 · 4 answers · asked by m_carl 1 in Mathematics

A net torque of 36 N·m is applied to a disk with a rotational inertia of 10 kg·m2. What is the rotational acceleration of the disk?
_______ rad/s2

2007-12-12 13:48:18 · 1 answers · asked by shamsan_415 1 in Physics

How many ordered quadruples (w,x,y,z) of positive integers are there with w+x+y+z=40

2007-12-12 13:47:43 · 1 answers · asked by Anonymous in Mathematics

I've heard the term "indigo child" and "crystal child" what some other classifications and are there legitimate test for knowing what catagory someone is under?

2007-12-12 13:43:11 · 6 answers · asked by Mushaw! 3 in Paranormal Phenomena

at an angle of 37 degrees w/ respect to the horizontal and the cannonball is 7m above the ground at this time.
a. What is the maximum height above the ground reached by the cannonball?
b. Assuming the castle walls and lands backdown on the ground, at what horizontal distance from its release point will it lands?The y-axis points up.

2007-12-12 13:37:49 · 2 answers · asked by elle 2 in Physics

I am doing a report and i am looking for some ideas. specific details are best, please!

2007-12-12 13:36:50 · 4 answers · asked by Bella 1 in Mathematics

2007-12-12 13:35:53 · 2 answers · asked by Anonymous in Weather

what are 2 temperature scales that scientists use

2007-12-12 13:35:03 · 4 answers · asked by Anonymous in Other - Science

how does hurricanes and physics relate

2007-12-12 13:34:33 · 1 answers · asked by SlimthugPaulWallMikeJones 1 in Physics