Science & Mathematics - 12 November 2007

The question is that there is a amusement park and in one of the rides the riders stand with their backs against the wall of a spinning vertical cylinder. The floor falls away and the riders are held up by friction. The acceleration of gravity is 9.81m/s^2. The radius of the cylinder is 8m and I have to find the minimum number of revolutions per minute necessary when the coefficient of static friciton between a rider and the wall is 0.5. I have to answer is rev/min. I asked this question before but with different values but I don't get how the person got the answer (1/2π)*√(9.8/0.6*10) ≈ 0.064rev/s when I do it I get 0.2.

2007-11-12 12:15:15 · 1 answers · asked by glance 3 in Physics

2007-11-12 12:14:08 · 3 answers · asked by Anonymous in Zoology

2007-11-12 12:13:39 · 1 answers · asked by tarzan49911 1 in Geography

What were the habits of the Dilophosaurus dinosaur?

2007-11-12 12:13:03 · 2 answers · asked by Anonymous in Zoology

Fing the slope of the midsegment of trapeziod ABCD given A(-2,-2) B(0,4) C(8,8) and D(4,-4). it has to be ether -1/3 or 1/2 or 3 or -2 thanks

2007-11-12 12:10:07 · 1 answers · asked by ☮ 5 in Mathematics

please help :)

2007-11-12 12:07:23 · 4 answers · asked by inkboy 2 in Geography

I have three questions i'm stuck on, please help.

1) A pool ball leaves a 0.60-meter high table with an initial horizontal velcity of 2.4m/s. Predict the time required for the pool ball to fall to the ground and the horizontal distance between the table's edge and the ball's landing location.

2)A soccer ball is kicked horizontally off a 22.0-meter high hill and lands a distance of 35.0 meters from the edge of the hill. Determine the initial horizontal velocity of the soccer ball.

3)A long jumper leaves the ground with an initial velocity of 12 m/s at an angle of 28-degress above the horizontal. Determine the time of flight, the horizontal distance, and the peak height of the long-jumper.

2007-11-12 12:05:31 · 1 answers · asked by That one guy 3 in Physics

(6x-3y+2)dx - (2x-y-1)dy=0

x^4 y' = -x^3 y - csc(xy)

[1+ y tan(xy) ]dx + x tan(xy) dy = 0


thanks

2007-11-12 12:03:47 · 1 answers · asked by enhein 1 in Mathematics

Was there an empty universe?

If their was just the singularity with all the matter in the present universe in it. Where did that matter come from?

And what existed before the singularity?

2007-11-12 12:01:09 · 20 answers · asked by Anonymous in Astronomy & Space

2007-11-12 11:56:41 · 2 answers · asked by leslie h 1 in Biology

Provide an overview of cellular respiration describing the three main parts:

Glycolysis
Krebs Cycle
Electron Transport Chain

I have a test on this tomorrow, and I don't understand what to do, please someone help me.

2007-11-12 11:54:08 · 1 answers · asked by s_shaikh 2 in Biology

Can some please explain how you get the answer to this geometry question?

A rancher has enough material for 271 meters of fence. She knows that a circle maximizes the
area-to-perimeter ratio, but a circular fence is too difficult to construct. She decides to simulate a circle
by building a fence in the shape of a regular polygon with as many sides as possible, but with not less
than five and not more than 15 sides. If she wishes to make each side a length of an even meter, and she
wishes to have no more than 2 meters left over, which regular polygon would you recommend she build,
and how long would each side be?

2007-11-12 11:54:02 · 1 answers · asked by Anonymous in Mathematics

2007-11-12 11:52:53 · 3 answers · asked by redgee 1 in Zoology

2007-11-12 11:51:23 · 3 answers · asked by Adis B 2 in Biology

2007-11-12 11:51:14 · 4 answers · asked by A T 1 in Biology

How do you, as a layperson, decide what you think is science and what you think is pseudoscience?

Of course, there are elements in science that fit well into common technology that we prove daily (no one denies the existence of microwaves or the legitimacy of aspirin, for instance); but I'm curious about the things scientists know but can't prove to the general public (either because it's not applicable to technology, because the proofs require extensive educations to understand, or both).

How do you separate the astrology from the astronomy, the chemistry from the alchemy, the cutting edge from the science fiction? If someone tells you about a spectacular new medical technology, how do you decide if it's a great breakthrough or a snake-oil health fad?

I work in physics (quantum and particle physics), and I'm curious about perspectives on this matter from people who aren't scientists; I'm curious how everyday people decide what to trust as legitimate and what not to trust.

2007-11-12 11:50:20 · 3 answers · asked by Anonymous in Other - Science

How do you, as a layperson, decide what you think is science and what you think is pseudoscience?

Of course, there are elements in science that fit well into common technology that we prove daily (no one denies the existence of microwaves or the legitimacy of aspirin, for instance); but I'm curious about the things scientists know but can't prove to the general public (either because it's not applicable to technology, because the proofs require extensive educations to understand, or both).

How do you separate the astrology from the astronomy, the chemistry from the alchemy, the cutting edge from the science fiction? If someone tells you about a spectacular new medical technology, how do you decide if it's a great breakthrough or a snake-oil health fad?

I work in physics (quantum and particle physics), and I'm curious about perspectives on this matter from people who aren't scientists; I'm curious how everyday people decide what to trust as legitimate and what not to trust.

2007-11-12 11:49:45 · 8 answers · asked by Anonymous in Other - Alternative

2007-11-12 11:46:53 · 2 answers · asked by Anonymous in Geography

2007-11-12 11:46:05 · 4 answers · asked by mart 1 in Geography

i thought amoebas & paramecium have nuclei. but prokaryotes don't have a nucleus... so are they eukaryotes?

2007-11-12 11:45:04 · 1 answers · asked by strictly_maggie 3 in Biology

im doing a project due thurs. noev 15th. and all i need to know is if natural gas has any waste products?!?!?! lol

2007-11-12 11:43:22 · 2 answers · asked by Ashley B 1 in Other - Science

In marine systems, the ecological pyramid is often inverted, i.e. there is less biomass of the first trophic level (phytoplankton) than on the second one (zooplankton, small fish, etc). How is that possible if primary producers maintain the rest of the ecosystem?

2007-11-12 11:43:08 · 1 answers · asked by Anonymous in Biology

"A high fat diet is bad" is something we accept but it has been proved to be false. Today, almost everyone will tell you that a diet high in fat is bad for you but evidence has proven that a high fat diet is not necessarily dangerous

2007-11-12 11:42:47 · 3 answers · asked by Dalila 1 in Medicine

A right circular cylinder is inscribed in a cone with height h and base radius r. Find the largest possible volume of such a cylinder.

2007-11-12 11:39:55 · 1 answers · asked by bosankasam 2 in Mathematics

And why?? Does it have anything to do with haploids/diploids?

2007-11-12 11:38:45 · 6 answers · asked by Anonymous in Biology

How is a big ball of gas concidered a planet? I mean you can't even walk on it? I always thought gas wasn't a solid so how can it be called a PLANET? Please explain thanks?

2007-11-12 11:37:45 · 9 answers · asked by Anonymous in Astronomy & Space

2007-11-12 11:35:06 · 2 answers · asked by miss_michellerely 1 in Biology

This energy is not available, the parts slow down and the clock shows time lost. A clock outside this frame of reference operates normally; this is in compete agreement with the theory of relitivity. An atomic clock will be affected in the same way, it operates with motion, the vibrating cesium crystal is still a form of motion. Science says that time and space came into being when the first sub atomic particle condensed from the singularity, what actully came into existance was motion and space, there was no time. It is motion and space that make the fabric of the universe, motion is the pulse of the universe. The theory of relativity has been ratified hundreds of times, an observer riding a beam of light would see the rest of the universe as being frozen because motion would not be detectable. Change the word, time, to motion,and nothing changes, everything becomes easier to understand, and time travel will no longer be a subject of discussion. H.B. Long.

2007-11-12 11:34:26 · 2 answers · asked by johnandeileen2000 7 in Physics

he said that the earth could shift causes lots of volcanos, tsunamis, etc.

2007-11-12 11:33:56 · 9 answers · asked by Anonymous in Astronomy & Space

2007-11-12 11:33:31 · 2 answers · asked by speedy21747 2 in Biology