Science & Mathematics - 20 September 2007

Solve..

7x^2 + y^2 = 64
x + y = 4

I dont get it with there being squared signs in.. I can do simultaneous equations usually...

This work is due in tomorrow by the way!

Thanks...

2007-09-20 10:39:51 · 6 answers · asked by CARLY-R-1991 2 in Mathematics

Suppose you held a proton, a neutron, and an electron in you hand. How can you tell them apart?

2007-09-20 10:38:56 · 3 answers · asked by vennysweetgirl21 3 in Physics

Suppose an astronaut drops a feather from 1.2 m above the surface of the Moon. If the acceleration due to gravity on the Moon is 1.62 m/s^2 downward, how long does it take the feather to hit the Moon's surface?

Please show work!

2007-09-20 10:36:30 · 3 answers · asked by cahill_hooker 2 in Physics

If he landed 56.6 m away at the same hiehgt at which he was fired, how long was he in the air?

If you could show all your work it'd be greatly appreciated!! =)

2007-09-20 10:36:02 · 2 answers · asked by xplozno8 2 in Physics

it is used to measure the strength and direction of the linear relationship between two quantitative variables. It is usually written as r.
i uderstand what it is but, i just don't understand why it is between -1 and 1.
could someone please clarify this point for me.

Thanks

2007-09-20 10:35:47 · 3 answers · asked by kris 2 in Mathematics

Geez.. i don't get this science **** hahah

2007-09-20 10:34:11 · 5 answers · asked by Anonymous in Physics

Predict the products of the single replacement reaction
Fe(s) + CuSO4(aq) → ?

a. Cu(s) + FeSO4(aq)
b. Fe(s) + Cu(s) + SO4(aq)
c. CuS(s) + Fe2SO4(aq)
d. FeCuSO4(aq)
e. FeO(s) + CuSO3(aq)

2007-09-20 10:33:54 · 1 answers · asked by Anonymous in Chemistry

2007-09-20 10:33:02 · 2 answers · asked by sweetie 1 in Earth Sciences & Geology

I need help, what is 2+2. HELP!

2007-09-20 10:31:16 · 12 answers · asked by Alan W 2 in Mathematics

A cyclist maintains a constant velocity of
6:7 m=s headed away from point A. At some
initial time, the cyclist is 253 m from point A.

What will be his displacement from his
starting position after 81 s? Answer in units
of m

What will be his position from point A after
that time? Answer in units of m.

2007-09-20 10:30:53 · 3 answers · asked by Jarod S 2 in Physics

Please, I need this before tomorrow morning! Thanks.

2007-09-20 10:30:38 · 1 answers · asked by sean77771 1 in Physics

2007-09-20 10:28:27 · 7 answers · asked by Bunbury 2 in Geography

I'm a soldier, and my fellow soldiers and I get together once a weekend and try to brainstorm up ways to defeat the IED threat. We've dreamt up hundreds of variations of our present day armor but the fact we keep running into is weight issues if we keep tacking on armor our vehicles will be over-burdened with weight issues and everything from suspension to transmission to motor problems occur. We need a chart to compare strength and weight. Until we figure out a solution our buddies will keep on dying and 60% of all our thoughts will still be directed towards defeating this threat. Please help. Thanks.

2007-09-20 10:28:20 · 3 answers · asked by Jason 2 in Earth Sciences & Geology

-12 + 5????

2007-09-20 10:26:53 · 9 answers · asked by lola c 2 in Mathematics

The displacement (in centimeters) of a particle moving back and forth along a straight line is given by the equation of motion s = 5sin(t) + 5cos(t), where t is measured in seconds.

a) Find the average velocity during the time period [1, 2].
cm/s

(b) Find the average velocity during the time period [1, 1.1].
cm/s

(c) Find the average velocity during the time period [1, 1.01].
cm/s

(d) Find the average velocity during the time period [1, 1.004].
cm/s

(e) Estimate the instantaneous velocity of the particle when t = 1.
cm/s

2007-09-20 10:24:59 · 1 answers · asked by Anonymous in Mathematics

Ball thrown down from 220 ft building with initial velocity of -22 ft/s
What is its initial velocity after 3 seconds. What is its velocity after falling 108 ft
Position function s(t)= -16t^2 +Vot +So
vo=initial velocity
The part for what is the initial velocity after 3 seconds i got. i just took the derivative of the position function. I don't understand how to do the second part Someone please show me the steps to find velocity after falling 108ft

2007-09-20 10:23:29 · 2 answers · asked by Anonymous in Mathematics

2007-09-20 10:23:05 · 1 answers · asked by Thursday 1 in Biology

Ethanol (C2H5OH) is synthesized for industrial use by the following reaction, carried out at very high pressure.
C2H4(g) + H2O(g) C2H5OH(l)
What is the maximum amount of ethanol that can be produced when 1.3 kg of ethylene (C2H4) and 0.013 kg of steam are placed into the reaction vessel?

I am confused as to how I answer this question. Can someone show me how to work it out?

2007-09-20 10:22:37 · 2 answers · asked by sn1per0nther00f 3 in Chemistry

I was given this exercise but I think that something is not right.

I) Let a , b y c three natural numbers so that
3D( a , c ) = 5D( b , c ) (D = Greatest common divisor)

i ) Prove that a is a multiple of 5 and that b is a multiple of 3

This is obvious. I wrote this part because it's necessary to solve the rest of the exercise.

ii) Find N = "xyzy" (x, y, z and y are the digits) knowing that N is a multiple of 5 and that N is a multiple of 9 and that the number "xy" is equals to the number "zy" +10

iii) If 100 ( a + b) + (c / 3) where N is the number found in ii), a is a 2 digits number and a is a multiple of 3 , number of divisors of a = 8 and m( b , c ) = 5985 (m= least common multiple), then find a , b y c

I get two numbers N, 5040 and 9585 but I can't find any solution for the part iii. Perhaps I am missing something. I'd like some of you to tell me what the problem is

a is a multiple of 15 (a= 30 to me), so is c, and b is a multiple of 3

2007-09-20 10:16:09 · 2 answers · asked by MathTutor 6 in Mathematics

2007-09-20 10:15:56 · 9 answers · asked by Anonymous in Biology

2007-09-20 10:14:00 · 2 answers · asked by Spades 1 in Chemistry

It's for extra credit in my math class. If you can help, thanks a lot:)

2007-09-20 10:13:23 · 6 answers · asked by David K 1 in Mathematics

My father is 5ft 10, my mother 5ft 6 and I, at 18, am 5ft 8.

I just wanted to know if anything else contributes to the growth (height) of a person apart from it being written in the genes?

2007-09-20 10:13:12 · 4 answers · asked by JTB 2 in Biology

Can someone please show me an example just by showing the statements?

Given: S is the midpoint of segment RT
AX=ST
XP=RS

Prove: X is the midpoint of segment AP

2007-09-20 10:11:47 · 2 answers · asked by Anonymous in Mathematics

well..not really global warming but still.

Alot of people are saying the world is runing out of water..
i dont really belive in that...considering 70 sumthing percent of the world is water.. dont give me a "salt water cant be drunk" thing..because you can make it drinkable.. but thats besides the point.

so if were really "runing out of water" i say we do nothing about this..i say we dont conserve water..because apparently the ice caps will melt and the earth will flood.

so if we waste water...theres really no problem..because we're going to get alot more of it when the ice caps melt.

so waste water...if we waste enough..mabey the ice caps melting will even it all out eh?

if you disagree with me..

dont give me a, "your an idiot that would never work" answer

give me a "your an idiot, that would never work, BECAUSE" answer.

2007-09-20 10:10:57 · 8 answers · asked by leroy jenkins 2 in Earth Sciences & Geology

2007-09-20 10:10:47 · 6 answers · asked by jay m 1 in Chemistry

In simple understandible words...if possible

2007-09-20 10:09:10 · 5 answers · asked by Anonymous in Chemistry

2007-09-20 10:08:28 · 4 answers · asked by Sandra G 1 in Medicine

A particle moves along a straight line and its position at time t is given by s(t)=2t^3–18t^2+30t where s is measured in meters and t in seconds.
What is the TOTAL distance travelled by the particle between time 0 and 12?

2007-09-20 10:07:09 · 6 answers · asked by Bikki 3 in Mathematics

These are the types that i need explained to me:

Nuclear
Chemical
Gravitational Potential
Elastic Potential

Can somebody please explain each of these to me using simplistic terms.

Thanks.

2007-09-20 10:04:04 · 2 answers · asked by Ahpro 2 in Physics