Science & Mathematics - 29 October 2007

Without being able to feel, a robot can never be motivated to improve itself intellectually. Only pain or pleasure can motivate anyone to self-perfect. Right?

2007-10-29 18:00:30 · 2 answers · asked by Anonymous in Other - Science

A bullet of mass 12g strikes a solid surface at a speed of 300 m s^ -1. The bullet penetrates to a depth of 3.0 cm.

(i) Calculate the average force resisting the motion of the bullet in the solid.

The solution:

F = ma
= 0.012 * (-1.5) * 10^6
= -18 000 N

Average resistive force is 18 000 N

Why is it that the force is positive? Why can't we just leave it as negative? Why must we must change it to positive?

2007-10-29 17:59:29 · 3 answers · asked by Anonymous in Physics

A Sphere with a radius x-1/2 is floading in a cylindrical tank of water with a radius (x-1). Determine the volume of water in the tank. Express your answer as polynomial in factored form. Leave your answer in exact form.

Formula
PI (radius)^2 (height)-4/3 PI (radius)^3

PI(x-1)^2(x+4/6)-4/3(PI)(x-1/ 2) ^3

PLEASE HELP!!! (factor then simplify)
Thanks :)

2007-10-29 17:58:07 · 1 answers · asked by C L 1 in Mathematics

for the problem y = 4 cos (x/2 + pi/2) there are 2 ways to discover the period.

1. period = 2pi/b and in this case (x/2 + pi/2) = 1/2(x + pi)
thus 2pi/.5 = 4pi

2. however when I try and solve algebraically for the inequality:
0 less than equall to 1/2(x+pi) less than equall to 2pi
I always get an interval of -pi, pi wich has a period of 2pi.

What am I doing wrong in # 2?

2007-10-29 17:57:37 · 3 answers · asked by skibum 2 in Mathematics

2007-10-29 17:53:58 · 26 answers · asked by Anikin 1 in Astronomy & Space

determine the total area of the trapazoid
A=1/2(base1+base2)height

1/2[x-2/1+X+12x-9/2x^2-x-3](3-2x/x3+27)

Express your answer as a rational expression (single fraction) in factored form...

THANKS GUYS!!!

2007-10-29 17:53:26 · 1 answers · asked by C L 1 in Mathematics

A highway patrol plane flies 3 mi above a level, straight road at a steady 120 mi/h. The pilot sees an oncoming car and with radar determines that at the instant the line-of-sight distance from plane to car is 5 mi the line-of-sight distance is decreasing at the rate of 160 mi/h. Determine the car’s speed along the highway.

2007-10-29 17:52:34 · 2 answers · asked by Blesson 2 in Mathematics

2007-10-29 17:48:54 · 2 answers · asked by Anonymous in Medicine

describe the set {1,5,7,8} using union and intersection

2007-10-29 17:44:08 · 3 answers · asked by nikkecola17 3 in Mathematics

Find an exponential function of the form f(x)=ba^x+c with y-intercept 2, horizontal asymptote y=-2, that passes through the point P(1,4).
a. f(x)=-2(2^x)
b. f(x)=2(2^x) -2
c. f(x)=2(1.5^x)-2
d.f(x)=4(1.5^x)-2

2007-10-29 17:42:56 · 2 answers · asked by austin 1 in Mathematics

Shouldn't our speed remain constant? No galaxies should affect any other gravitationally because the big bang should move all matter away from eachother, and yet we see galaxies running into eachother. I feel so small.

2007-10-29 17:41:38 · 10 answers · asked by akabryanhall 2 in Astronomy & Space

If everything originated from the same explosion, shouldn't all matter be traveling at the same speed, and wouldn't this create a sphere of sorts, with nothing but space where the bang originated?

2007-10-29 17:38:50 · 2 answers · asked by akabryanhall 2 in Astronomy & Space

The starting equation was 1/√x which i plugged into the theorem and got this {(x^(1/2) - (x+h)^(1/2)}/{h(x+h)^1/2(x)^(1/2)} So i changed it to ^1/2 to make it eaiser. But i can not figure out how to get the h out of the top to cancel out the bottom so i can plug 0 in for h. Any help on the 2nd step would be wonderful.

Thanks,

Brad

2007-10-29 17:38:48 · 4 answers · asked by Brad25 1 in Mathematics

we did peer evaluation in class and the math teacher wrote the answers on the board. the following questions i got wrong. but i dont understand how. are these answers right or did my math teacher miscalculate.?

2/3 +3/4 i got 15/12 and in simplified form i got 1 1/4

2/3 + 5/6 i got 9/6 and in simplified form i got 1 1/2

1 1/6 + 2 1/2 i got 88/ 12 in simpilfied i got 9 1/3

1 1/3 + 2 3/8 i got 157/24 in simpilfied for i got 6 13/ 24

please explain

2007-10-29 17:37:49 · 7 answers · asked by Anonymous in Mathematics

Find the exact solution to the equation 3^x+5=9x.
a. 5/3
b. 5/2
c. 5
d. 6

2007-10-29 17:37:11 · 4 answers · asked by austin 1 in Mathematics

2007-10-29 17:36:19 · 5 answers · asked by I Love Lamp!!! 1 in Biology

What is 5/8 (1/4 / 1/2) =

2007-10-29 17:34:19 · 9 answers · asked by acuraboy1978 2 in Mathematics

Find the density and first ionization energy for sodium, potassium, magnesium, and calcium. What do these values predict will happen physically (not chemically) when each is added to water?
Which will be easiest to oxidize?
Which will be the hardest to oxidize?

Na- Density: .968g/mL; IE: 496kJ/mol
K - Density: .856g/mL; IE: 419kJ/mol
Mg - Density 1.738g/mL; IE: 738kJ/mol
Ca - Density 1.55g/mL; IE: 590kJ/mol

Thank you for any help!

2007-10-29 17:33:17 · 2 answers · asked by Anonymous in Chemistry

So I had this weird occurrence a few weeks ago- I took 35 percocet (5 mg oxycodone, 350 mg of acetaminophen per tablet) and well nada happened. Literally (well aside of passing out and vomiting all night and the next day).

This thing puzzles me a lot , I read that 10 mg of acetaminophen is supposed to cause damage to the liver, yet it apparently did not .
How is this possible? -Can pharmacokynetics vary that much ? I am 180 lbs and generally healthy (exercise a lot, follow healthy diet, do not drink at all) but it was over 13 g for christ sakes.

I seem to have high tolerances to some medication (namely for example I can take over 10 mg of ativan and not pass out -I will be quite sleepy, but generally can function) , -I was told that some people pass out from as little ast 1.5 mg.

Can it be some sort of disorder?

2007-10-29 17:32:41 · 4 answers · asked by Max B 1 in Medicine

how do you do the u-substitution for this..i mean like what is u? du? dv? v? how could u figure out which is which?
i thought
u= x dv= lnxdx
du= xdx v= 1/x

2007-10-29 17:28:32 · 5 answers · asked by tc 1 in Mathematics

If we can calculate how fast galaxies are moving, and in what direction, can't we pinpoint the original place of the big bang?

2007-10-29 17:28:09 · 8 answers · asked by akabryanhall 2 in Astronomy & Space

I'm supposed to write an essay on a controversial subject in medicine and it has to involve a drug (may or may not be the main point of the essay). Does anyone have any suggestion? Nothing on Vioxx, HIV vaccination (although those are very good subjects) Thank you!

2007-10-29 17:24:36 · 2 answers · asked by Yoshi 2 in Medicine

oh my JAH!
im really doomed with this subject..what is the key?

2007-10-29 17:22:45 · 7 answers · asked by Anonymous in Mathematics

If a CD rotates at 500 rpm while the last song is playing, and then spins down to zero angular speed in 2.60 s with constant angular acceleration, what is the magnitude of the angular acceleration of the CD, as it spins to a stop?

2007-10-29 17:20:22 · 1 answers · asked by KT 1 in Physics

I think it's produced in the stomach, and converted to pepsinogen by HCI to prevent damage to the stomach lining?

2007-10-29 17:13:13 · 7 answers · asked by Anonymous in Biology

Isn't algebra a little out dated? We now have computers that can graph and find all of the algebraic problems we need solved, like profit analysis for buisnesses. I am by no means saying abolish all algebra from schools, but merely to compact the course down to the absolute basics and necessities that will actually be used in most people's day to day life and careers and incorporate it into another mathematical course. I believe that to have multiple years of algebra be mandatory is a waste of government money. Shouldn't extensive study in this course only be optional for students going into a field of work that is algabraically heavy? What do you think?

2007-10-29 17:10:42 · 8 answers · asked by nsteedazx3 1 in Mathematics

You plan to earn $15 per week for a charity. Will you use estimation, mental math, paper and pencil, or a calculator to determine, how many weeks it will take you earn $1,000? Explain why.
(2) The monthly rate for a 3 year subscription to an online music service is $10. What is the total cost for 3 years?

2007-10-29 17:02:42 · 1 answers · asked by rosemariestewart64 1 in Mathematics

A city of 250,000 people is growing at a rate of 1.3% per year. Estimate the population of the city 30 years from now.

1. S(31) = 250,000(1.3)^(31-1)
2. S(30) = 250,000(1.3)^(30-1)

Which set-up is correct?

2007-10-29 17:01:38 · 1 answers · asked by James 1 in Mathematics

2007-10-29 17:00:15 · 10 answers · asked by sara e 1 in Botany

The sun rotates every 200 million years about the center of the milky way galaxy at a distance of 30,000 ly from the center. What is the mass of the galaxy and what assuptions were made?

2007-10-29 16:59:59 · 1 answers · asked by h_oboe 2 in Physics