Science & Mathematics - 19 September 2007

A block of mass m is released from rest at a height R above a horizontal surface. The acceleration due to gravity is g. The block slides along the inside of a frictionless circular hoop of radius R.

Which one of the following expressions gives the speed of the mass at the bottom of the hoop?

a. zero m/s^2
b. v^2 = 2gR
c. v^2=(g^2)/R
d. v = mgR
e. v = mg/2R

2007-09-19 13:10:08 · 2 answers · asked by lil_britt0737 1 in Physics

2007-09-19 13:09:31 · 3 answers · asked by curiousgeorge200 1 in Geography

1in= 2.54cm
12in= 1ft
1yard=36in
1m= 39.37in

and its supposed to be a 2-step english to metric conversion and are suppossed to use the guessing method (not actually guessing.... its a real method)

2007-09-19 13:08:57 · 5 answers · asked by Pheobe Halliwell 1 in Mathematics

i'm supposed to solve for x and y.

here is the problem

5-y=3x
y=2x

i don't understand it at all.
what so ever.

please help me.

please.

2007-09-19 13:08:05 · 24 answers · asked by lalala 2 in Mathematics

2007-09-19 13:07:35 · 3 answers · asked by eric j 1 in Mathematics

Emily takes a trip, driving with a constant velocity of 85.5 km/h to the north except for a 22 min rest stop. If Emily's average velocity is 66.8 km/h to the north, how long does the trip take?

2007-09-19 13:06:47 · 1 answers · asked by Pauly Walnuts 2 in Physics

Evaluate the indefinate integral of
(1+x)/(1+x^2) dx

The answer is 1/2 ln (1+x^2) + arctan (x)....

2007-09-19 13:06:09 · 3 answers · asked by rman1201 4 in Mathematics

2007-09-19 13:06:01 · 25 answers · asked by daz2001_uk 1 in Other - Science

i am looking for an outline of how to make a solar powered device used to heat water to kill bacteria or to cook with or to heat water and the total size of the devise can only be two foot square.



for the person who can give me the best outline i will pick as best answer, I promise, thanx to anyone who can help me.

2007-09-19 13:04:41 · 7 answers · asked by quennofda***world 2 in Engineering

Ok, i know this seems a little lazy but i can't seem to find any good science experiments. There arn't any good sites that can help me. All i want is an experiment dealing with water pollution or geology. I just can't find any experiments, all there is are projects. If you have a source, please list it, it will really help!

2007-09-19 13:03:22 · 1 answers · asked by In the Hospital 2 in Other - Science

2007-09-19 13:02:55 · 2 answers · asked by Anonymous in Other - Science

please explain

2007-09-19 13:02:54 · 2 answers · asked by eric j 1 in Mathematics

do you do distributive property first or combining like terms first?

2007-09-19 13:02:19 · 5 answers · asked by Anonymous in Mathematics

*= squared

if just not sure what to do when you get to the poing of combining like terms

ill get u started


(a*+2)(a*+2)

just multiply these

for other exponents, just do this (^#)

thanks

2007-09-19 13:01:43 · 4 answers · asked by Anonymous in Mathematics

please explain

2007-09-19 13:01:07 · 1 answers · asked by eric j 1 in Mathematics

Calculate the empirical formula of a compound that has the following percent composition: 7.195% P and 92.805% Br.

Work would be appreciated,

thank you very much

2007-09-19 13:00:16 · 4 answers · asked by aaadaj 1 in Chemistry

Want to know how to contact someone at dewalt tools about a tool that I know will sell big

2007-09-19 13:00:08 · 3 answers · asked by nickgranados 1 in Engineering

y = 3x + 1
so y intercept would be
0 = 3x + 1
3x = -1
x = - 1/3
how do u get - 1/3 from 3x = -1 ??
so wut would the y intercept be if y = 2/3x + 6

0 = 2/3x + 6
2/3x = -6
then wut?

2007-09-19 12:58:12 · 2 answers · asked by Anonymous in Mathematics

how does electrolisis works?does it need too much electricity to separate oxygen and hydrogen?if its ok please tell me how.thanks

2007-09-19 12:58:09 · 1 answers · asked by john 1 in Engineering

For the vectors given in Fig. 3-32 (|A| = 64.0 and = 58.0°), determine the following.

Figure 3-32
http://www.webassign.net/giancoli5/3_35alt.gif
(a) A - B + C
Magnitude
Direction ° (counterclockwise from the +x axis is positive)
(b) A + B - C
Magnitude
Direction ° (counterclockwise from the +x axis is positive)
(c) C - A - B
Magnitude
Direction ° (counterclockwise from the +x axis is positive)

2007-09-19 12:56:40 · 1 answers · asked by oxblackout12 1 in Physics

Mike is cutting the grass using a human-powered lawn mower. He pushes the mower with a force of 45 N directed at an angle of 41° below the horizontal direction. Calculate the work that Mike does on the mower in pushing it 9.1 m across the yard.

2007-09-19 12:56:12 · 3 answers · asked by lil_britt0737 1 in Physics

I'm in Alg II/Trig and I haven't done this stuff in a long time. I don't have my book with me and I can't find the answer online. I know it's not just adding the powers, like x^2 + x^3 = x^5, because that's how you multiply exponents. So how do you add, exactly? Is there even a way??

2007-09-19 12:56:08 · 8 answers · asked by tinomart99 3 in Mathematics

If anyone could explain how the following is done, it would be greatly appreciated!

Suppose that the gcd(a,b)=1. Prove that for every integer c, the equation ax+by = c has a solution in integers x and y (by finding a solution to au+bv=1 and multiplying by c).

2007-09-19 12:53:37 · 2 answers · asked by Fonzieo 1 in Mathematics

2007-09-19 12:51:25 · 4 answers · asked by Mike B 2 in Mathematics

2007-09-19 12:50:23 · 4 answers · asked by Anonymous in Medicine

2007-09-19 12:49:48 · 3 answers · asked by J L 2 in Chemistry

i just need the beginning...the rest i can probably manage.
express in the simplest radical form to the nearest hundredth:

x squared + 3 = 7x how do i fix it so it quals to 0 its really easy but i forgot lol.



2x squared + 1 = 4x
this one also. how/?

2007-09-19 12:49:27 · 5 answers · asked by curtismayfield? 2 in Mathematics

I'm doing a Science Fair Project that involves measuring white light. I know I have to use a white light meter, which I can just get from my teacher, but what unit can you use to describe the amount of white light?

2007-09-19 12:48:08 · 2 answers · asked by Anonymous in Other - Science

if its like y = 3x + 1
then the y-intercept would be 1.
because slope-intercept form is y = mx + b, and b is the y-intercept. so how would you find the x-intercept of that equation????

2007-09-19 12:48:04 · 6 answers · asked by Anonymous in Mathematics

No stupid answers please. This is for an extra credit assignment.

2007-09-19 12:45:24 · 6 answers · asked by ♫Lαurεn♪ 4 in Biology