Science & Mathematics - 14 November 2007

A person uses a crow bar to move a rock that weighs 200 N. The effort arm is 50 cm long. The resistance arm is 20cm long

2007-11-14 14:28:38 · 2 answers · asked by Anonymous in Engineering

Lim t-->0 (5^t-3^t)/t the answer is in the book, but how do I get it ln(5/3)?

2007-11-14 14:26:52 · 3 answers · asked by m_carl 1 in Mathematics

which observation below comes closest to explaining the basis for placing these organisms in different taxa?
a. some closely resemble animals, which lack cell walls
b. their cell walls are constructed form very different biochemicals
c. some have cell walls only for support
d. some have cell walls only for protection from herbivores
e. some have cell wasll only to control osmotic balance

2007-11-14 14:26:21 · 4 answers · asked by Colleen C 1 in Biology

A 85.0 cm diameter wheel accelerates uniformly from 220 rpm to 390 rpm in 7.0 s. How far will a point on the edge of the wheel have traveled in this time?

2007-11-14 14:25:41 · 2 answers · asked by Bob J 1 in Physics

A ball is thrown horizontally out the window of a building with a velocity of 8.0m/s from a height of 200m. How far from the base of the building will the ball land? (Use g=10m/s^2)

A. 115 m
B. 51 m
C. 90 m
D. 180 m
E. 60 m

2007-11-14 14:25:18 · 1 answers · asked by Anonymous in Physics

An electron and a positron each have a mass of 9.11x10^-31 kg. They collide and both vanish, with only electromagnetic radiation appearing after the collision. If each particle is moving at a speed of 0.10c relative to the laboratory before the collision, determine the energy of the electromagnetic radiation.
(answer is in Joules)

2007-11-14 14:24:57 · 2 answers · asked by allyn_03 2 in Physics

i do not know what the hell this means

2007-11-14 14:23:59 · 5 answers · asked by Sarah M 1 in Mathematics

2007-11-14 14:23:10 · 2 answers · asked by Tonie M 1 in Chemistry

A bicycle has wheels 0.94 m in diameter. The bicyclist accelerates from rest with constant accleration to 7.52 m/s in 5.57 seconds.

What is the angular acceleration of the wheels?


Then you are given

α= 1.47 rad/s/s and t=2.41 s.

How many revolutions does it go through?

2007-11-14 14:22:33 · 1 answers · asked by Anonymous in Physics

2007-11-14 14:18:35 · 1 answers · asked by Tonie M 1 in Mathematics

I've been trying to differentiate with my TI-89 but everytime i put something in it says "error: argument error". I borrowed my friend's Ti-89 and put in the exact same thing, the calculator gave me a derivative.
So i tested it again. I told it to "factor(x^2-9)" and it gave me the same thing "error: argument error"

What can i do to make it go back to giving me answers?!

2007-11-14 14:16:39 · 3 answers · asked by lunaa_madison 1 in Mathematics

Chemistry Questions that I need help on.

2007-11-14 14:16:18 · 1 answers · asked by Tonie M 1 in Chemistry

Manganese II nitrate + lead dioxide + nitric acid ----> hydrogen permanganate + lead II nitrate + water


(Could you please tell me the oxidation #'s for the original, too? :) )

2007-11-14 14:14:28 · 1 answers · asked by Anonymous in Chemistry

It has to relate with hypertonic solutions.

2007-11-14 14:12:35 · 2 answers · asked by LiL_Blu86 1 in Biology

2007-11-14 14:12:25 · 10 answers · asked by Anonymous in Mathematics

i have a science project...and i can't seem to find where a good place to ubild one is...
I knwo on a river
in an open area?
rainy?
uneven land?

2007-11-14 14:07:49 · 2 answers · asked by brieanna 1 in Engineering

1. 9x + 7 / 2 + 9x - 2 / 5 = -2/3
I came up with 73/179x.

2. (-4 - 9i)(-4 - 9i)
I came up with 16 - 81i^2

3. (r + 6)^2 = 13
I came up with r = -6 + sqrt 13 or r = -6 - sqrt 13

4. Absolute value of 3x - 4 >/equal to 8
I came up with x >/equal to 4/3

5. 10y = 7y + 6 + 2y
I came up with y = 6

How'd I do? If I screwed up, help would be appreciated!!!

2007-11-14 14:03:11 · 4 answers · asked by wrongnumber 1 in Mathematics

can someone explain to me why the fetus in the womb is a person and not just cells?

2007-11-14 14:02:29 · 36 answers · asked by Jen 2 in Biology

How can an organism exhibit a trait not passed by either parent?

2007-11-14 14:02:07 · 7 answers · asked by babe 2 in Biology

I've done some research and I'm now even more confused. was it a ufo

2007-11-14 14:01:39 · 21 answers · asked by Anonymous in Astronomy & Space

I'm just looking for the derivative of arccos

arctan- 1/(1+x^2)
arcsin- 1/sqrt(1-x^2)

2007-11-14 14:01:22 · 4 answers · asked by Anonymous in Mathematics

Ok the question is:

When you work harder, your muscle cells work harder and increase in size. How might various organelles in a muscle cell increase in size, number, or activity to respond to the challenge of an increased workload?

Please only answer if your 100 % sure of you're right. Thanks.

2007-11-14 14:00:26 · 4 answers · asked by Katie L 2 in Biology

the circumference of a circle and the perimeter of a square can intersect at a maximum of ? points

2007-11-14 14:00:25 · 2 answers · asked by Anonymous in Mathematics

DId the concept of higher physical dimensions exist in Maxwell's time? Has anyone explored the ramifications of modern GU theories on EM propogation or has it been somehow established that it is bound to ordinary 3D spacetime? What would be a test to determine if it was or not?

2007-11-14 13:59:16 · 1 answers · asked by AmigaJoe 3 in Physics

2007-11-14 13:57:25 · 11 answers · asked by xoxshortiee92x 1 in Biology

I was just wondering if ther eis such a thing as a programmable 9v motor, or even better a way to do the whole thing, im really into this subject right now, and i was wodnering where i can also refer to?

2007-11-14 13:53:35 · 3 answers · asked by Anonymous in Engineering

2007-11-14 13:53:12 · 5 answers · asked by tanrode 2 in Medicine

Thats it

2007-11-14 13:52:18 · 8 answers · asked by Cory J 2 in Mathematics

2007-11-14 13:51:09 · 5 answers · asked by ? 4 in Geography

Standard cell potentials are determined with 1.0 M solutions of ions. In this experiment, we will use 0.10 M solutions of Zn2+, Cu2+, Pb2+, and Ag1+ to minimize the amount of hazardous waste generated. In this series of questions, you will figure out what effect this will have on the voltages you observe.

Consider a cell consisting of a Cu2+/Cu couple, and a Ni2+/Ni couple.

a. Starting with 1.0 M solutions of ions (standard conditions), evaluate Q in the Nerst Equation.

2007-11-14 13:50:20 · 1 answers · asked by flaquita 1 in Chemistry