Science & Mathematics - 22 September 2007

Heat wise

2007-09-22 13:13:44 · 5 answers · asked by rosa c 1 in Astronomy & Space

A block of mass m = 2.7 kg is dropped from height h = 55 cm onto a spring of spring constant k = 1190 N/m (Fig. 8-38). Find the maximum distance the spring is compressed.

http://i225.photobucket.com/albums/dd182/jameslotobond/Chapter8Problem22.jpg

2007-09-22 13:13:31 · 1 answers · asked by James B 1 in Physics

Describe the path that a star on the celestial equator follows from the time it rises until it sets for a person at a latitude of 60 degrees N and a person at the equator

2007-09-22 13:13:01 · 1 answers · asked by Anonymous in Astronomy & Space

a. it has the same concentration as Cl- ion
b. its concentration is half that of Cl- ion
c. its concentration is twice that of the Cl- ion
d. itsconcentration is one-third of the Cl- ion

2007-09-22 13:12:53 · 1 answers · asked by Anonymous in Chemistry

Because to see in the dark, your pupils (irises, or whatever) get bigger to allow in more light. But the clearest images are produced by pinhole cameras (where the hole is as small as possible).

So is our night vision actually inherently blurry because of the wider aperture? Or do our eyes focus it to normal anyway?

2007-09-22 13:12:04 · 2 answers · asked by a forest nymph 3 in Physics

In the Figure, a horizontal force Fa of magnitude 22 N is applied to a 2.9 kg book as the book slides a distance d = 0.6 m up a frictionless ramp at angle θ = 30°. The book begins with zero kinetic energy. What is its speed at the end of the displacement?

http://i225.photobucket.com/albums/dd182/jameslotobond/Chapter7Problem20GO.jpg

2007-09-22 13:11:02 · 3 answers · asked by James B 1 in Physics

A loaded penguin sled weighing 87 N rests on a plane inclined at angle θ = 22° to the horizontal (Fig. 6-28). Between the sled and the plane, the coefficient of static friction is 0.26, and the coefficient of kinetic friction is 0.18. (a) What is the minimum magnitude of the force , parallel to the plane, that will prevent the sled from slipping down the plane? (b) What is the minimum magnitude F that will start the sled moving up the plane? (c) What value of F is required to move the sled up the plane at constant velocity?

http://i225.photobucket.com/albums/dd182/jameslotobond/Chapter6Problem20.jpg

2007-09-22 13:07:27 · 2 answers · asked by James B 1 in Physics

A broad jumper begins his jump at an angle of 22.0 degrees from the horizontal. At the middle of the jump he reaches a height of 70.0 cm. What is the horizontal velocity?

2007-09-22 13:06:55 · 2 answers · asked by Anonymous in Physics

2007-09-22 13:06:07 · 3 answers · asked by Anonymous in Mathematics

A common flea is recorded to have jumped as high as 21 cm. Assuming that the jump is entirely in the vertical direction and that air resistance is insignificant, calculate the time it takes the flea to reach a height of 7.0 cm.

the answer is 0.04 s. i know how to get it, but i don't get why.
so i plugged it into that equation:
delta y = (initial velocity)(delta T) + (0.5)(acceleration)(time-squared)

0.07 = 0 + (0.5)(9.81)(time-squared)
t=0.12

so i divided 0.12 by 3. and i got 0.04 seconds.
why do you divide by 3? 7 cm is already a third of the highest jump of the common flea. wasn't i calculating the 7.0 cm jump time? not the 21 cm one?

or did i just completely fail at this problem?
help, thank you.

2007-09-22 13:05:15 · 1 answers · asked by Anonymous in Physics

pls give me da detail steps

2007-09-22 13:05:09 · 2 answers · asked by aham brahmasmi 2 in Mathematics

2007-09-22 13:03:08 · 32 answers · asked by Anonymous in Botany

Solve this and show work

dy/dx = (2x^2+1)/(xe^y) , x>0

2007-09-22 13:01:40 · 3 answers · asked by Lois C 1 in Mathematics

can anybody tell me the temperature and brightness of stars, distances, names of stars, nearby constellations, galaxies, and nebulas, time of year or date to best view the constellation, myths or storeies assocaiated with constellation, and any other points you feel are necessary? Thanks i'll give you 10 points if you tell me all these information.

2007-09-22 12:55:59 · 2 answers · asked by Anonymous in Astronomy & Space

2007-09-22 12:54:26 · 2 answers · asked by torie 1 in Weather

2007-09-22 12:52:36 · 13 answers · asked by kev 2 in Weather

Please show a source! (Credible, of course)

2007-09-22 12:45:52 · 2 answers · asked by Anonymous in Chemistry

A train pulls away from a station witha constant acceleration of .4m/s^2. A passenger arrives at at point next to the track 6s after the end of the train has passed the very same point. What is the slowest constant speed at which she can run and still catch the train?

2007-09-22 12:45:46 · 1 answers · asked by Anonymous in Physics

2007-09-22 12:45:17 · 7 answers · asked by jr 2 in Mathematics

(There are also small pieces of aluminum inside the can.)

2007-09-22 12:44:03 · 2 answers · asked by jkgregory10@sbcglobal.net 1 in Chemistry

Its CuSO4 + Na2CO3 produces CuCO3 + Na2SO4 and I need to find the percent yield, and CuCO3 is the precipitate. My theoretical yield is 0.615 g but for the actual yield I got 0.116 g so I was wondering what other people may have gotten for their actual mass.

2007-09-22 12:41:38 · 1 answers · asked by <3DA<3 1 in Chemistry

2007-09-22 12:41:26 · 13 answers · asked by hellokool 1 in Astronomy & Space

Their special qualities as Ghosts, invisibility,lack of physical mass, etc.They would be invaluable in mine cave-ins and as a Spy or in Investigation.IS there any way we can tap into their special powers?Would they cooperate or do they resent us?How could we reward them for their help?Paranormal investigaters and other ghost experts.What do you think?

2007-09-22 12:40:36 · 10 answers · asked by Dr. NG 7 in Paranormal Phenomena

How many moles of Cl2 would you need to add to have stoichiometrically equivalent amount of Na and Cl2?

2Na+Cl2 ---> 2NaCl

2007-09-22 12:40:34 · 2 answers · asked by Molly❀ 3 in Chemistry

2007-09-22 12:36:57 · 3 answers · asked by Anonymous in Physics

Here is problem in original form.

Find the point(s) where the tangent line to f(x)=((x^2)-1)(x+7) is perpendicular to the line y=(1/2)x+7

Here is what I have done:

y=(1/2)x+7 so m=1/2 and perpendicular slope is -2

I do not know where to go on because I am very, very tired...I have slept only 7 hours in the past 48 hours, so please help.

2007-09-22 12:34:23 · 3 answers · asked by pyrojelli 2 in Mathematics

Calculations done on page 253 of information provided by Maharishi Mahesh Yogi in book on Bhagavad -Gita.

2007-09-22 12:31:19 · 4 answers · asked by Washington 2 in Physics

A 0.8000 g sample of impure sodium choride is dissolved in water, and the chloride is precipitated with excess silver nitrate, producing 1.000 g of silver chloride. What is the mass percent of sodium chloride in the original impure sample?

a. ) 40.77
b. ) 24.74
c. ) 50.97
d. ) 80.00
e. ) 0.6977

I worked it out and I got e). Is that correct?

2007-09-22 12:29:39 · 2 answers · asked by secondaryhoper 1 in Chemistry

15x= 350 + x^2

2007-09-22 12:28:44 · 7 answers · asked by Anonymous in Mathematics

2007-09-22 12:28:31 · 7 answers · asked by aretwo_d2 3 in Weather