Mystery Definition and 913 Threads

Homework Statement A passenger in a helicopter traveling upwards at 17m/s accidentally drops a package out the window. a)If it takes 13s to reach the ground, how high to the nearest meter was the helicopter when the package was dropped? b)what was the maximum height of the package above the...

http://www.msnbc.msn.com/id/28622042/

Irene Klotz, Discovery News, 12th Jan 09- http://dsc.discovery.com/news/2009/01/12/strange-light-hubble.html and from the Hubble site- http://hubblesite.org/newscenter/archive/releases/2009/04/

how come some computer parts double they're power once in like 18 months or so? it's kind of weird...alwais +100% and in 18 months or so...for example take the RAM memory...they came like this(in MB): 8,16,32,64,128,256,512,1024,2048,4096,8192! I didn't cheked,but the 16 GB RAM stick might be...

Just found this article...thought you guys may want to check it out. http://www.space.com/scienceastronomy/090107-aas-loud-cosmic-noise.html

Hello to all! I have but 1 simple question: Has the secret of Nikola Tesla's ability to run a car on power from "the ethos" ever been revealed? Was it a permanent magnet motor the didn't need an external power source? I can see all the skeptics eyebrows being raised as we speak regarding...

Hi all :D, I was wondering if someone could help me. My physics teacher once told me about this unsolved mystery - and I have a vague memory of it. I was hoping someone could help me find out what it is. Basically it was something to do with astronomy and about a Greek astronomer. I...

Homework Statement The following five points lie on a function: (1,20) (2,4) (5,3) (6,2) (10,1) Find an equation that passes through these points and has these features: a. There are three inflection points b. There is at least one local maximum c. there is at least one local...

What is the explanation for the tide on the surface of the Earth opposite the moon?

Can anybody explain why my numbers are not equally out? At work, I am trying to determine the heat transfer taking place in a water cabinet. Both loops have water in them. There is a counter current flow heat exchanger where the transfer takes place. I take the temperature measurements...

I don't understand what really is happening. When there is fog on the (inside)windshield of my car, I turn on the AC and it goes away. Are the water droplets freezing? Am I changing the dew point? Why does it go away? If I leave the temperature at 62F, the fog increases. Can somebody...

My kitchen window looks into an (out house) the out house is where i keep my bikes so it is securely locked. So at night i am cooking a meal and see my reflection in the window just as clear as in a mirror. I am wearing a stripey jumper which also shows clearly in the reflection, as i move...

If someone dies in a hospital a member of medical staff tries to brings their heart back to life, sometimes this works. Why if someone dies of nateral causes can't their heart be braught back to life after a while?

I was going to have baked potatoes for lunch so i put them in the oven on high, half an hour later the houses filled with smoke, it is still lingering now, what ever had spilled over in the oven previously must have burnt and burnt and burnt, strange as the last thing i baked did not cause any...

I was looking at my periodic table in Chemistry today and noticed that Chlorine's relative mass was 35.5, how can it have half an amu when it has 17 electrons? That's not 0.5amu, is it?

I was out for a wander yesterday when I stumbled across a little run-down hut with 3 walls and no door. Inside was a table, 3 chairs, remnants of some candles and a pile of poppy seed heads. Written in pencil all over the table was some notation. It was mainly numbers set out in rows, arranged...

I love Gizmag, and they've presented a challenge. (Actually, Honda presented it; Gizmag is passing it on.) The link shows a Honda concept bike that appears to have no tires, suspension, or drive train. I can think of a few ways that the suspension, steering, and power system might be done...

I'm trying to figure out where I'm getting these bites from. Skeets or fleas or whatever. I've got about six bites in the soft crook behind my left knee. None behind the right knee. They are very itchy. They have been occurring over at least a week or more. Still occurring, in fact. I've...

1. Why does a crate on an accelerating truck accelerate backwards proportional to the amount of kinetic friction? I don't understand why the crate accelerates backwards as if kinetic friction was the only force acting on it. 2. Homework Equations : F=ma

Homework Statement http://img159.imageshack.us/img159/1867/es100wi8.th.png http://g.imageshack.us/thpix.php a) Write an expression for V1 and V2 both in time domain and phasor domain (Solved) b) Write an expression for the current I both in time domain and phasor domain (Solved) c) Calculate...

The question states: Ball bearing are made by letting spherical drops of molten metal fall inside a tall tower, and they solidify as they fall. a) If a bearing needs 4.0s to solidify, how high must the tower be? b) What is the bearing velocity when it reaches the bottom? c) What...

http://img.photobucket.com/albums/v235/gsan_bot/magnetic1.jpg" Refer to example 6.2 shown in the picture, the magnetic flux = -1.2t and the deriative time of magnetic flux should be -1.2, thus, the flux is decreasing and the direction of the induced current should be reverse. but why it say...

After doing some research on the subject I have managed to work out roughly how it works. What I havn't been able to find out is what it does. Were there any implications from this effect? Did it lead to disproving or proving a theory? Any help would be very usful.

The brain can sense the direction of a sound source by noting how much earlier a sound is heard in one ear than in the other. Model your ears as two sensors 19.0 cm apart. If a click from a distant source is heard 210 x 10^-6 s earlier in the left ear than in the right, from what direction...

I've been kicking myself in the head all day trying to figure this one out. I'm completely bewildered.:rolleyes: Please help meeee! A stone is thrown vertically upward at a speed of 43.00 m/s at time t=0. A second stone is thrown upward with the same speed 2.250 seconds later. At what...

http://www.wluctv6.com/news/news_story.aspx?id=185121 Video http://www.wluctv6.com/news/video.aspx?id=185121 They say that these lights have been observed for 40 years.

not able to pick up a 1 kg iron object off the ground by overcoming the gravitational force between Earth and the object. Consider this : It can pick up a 1 gram (iron) object easily. Then, the increase (from 1gm to 1 kg) would be by a 1000 times. Clearly that increase cannot account for the...

Help me out please, a friend sent this to me and I can't seem to figure it out. Thanks! "Congresswoman Smith opened the Post and saw that a bean-counting scandal had been leaked to the press. Outraged, Smith immediately called an emergency meeting with the five other members of the Special...

I still don't quite fully understand about the order of poles and calculating residues. Take f(z) = 1/sin z at z=0 for example. When I try putting that into Laurent expansion about z=0, 1/ sin z = 2i/ (e^z - e^(-z)) = 2ie^(-z) / ( 1 - e^(-2z)) = 2ie^(-z) [ 1 - e^(-2z) + e^(-4z) - e^(-6z) +...

Hello all. I have a dell inspiron 1525 laptop, and I've had it for about 4 months. I've been downloading music here and there, but nothing too major. Earlier this week I realized that my computer had used about 70gb of memory, and I had no idea where it was. So I downloaded a disk analyzer...

I'm curious as to why there aren't heavier metals in the Earth's core than iron and nickel. Why those two? Anyone have any insight?

Is it a turtle or a monster?? :) http://www.newsday.com/news/columnists/ny-lijoy0801,0,5138315.column

Who are you people that can type fast, where the heck did you learn this skill, it seems that there are people out there that can type with more than one finger, what the hey are you people mutants?

I've learned that photons have no mass, so why they are still influenced by black holes or other large celestial bodies?

Can someone give me a list of problems which at first sight require the axiom of choice, but do not?

free energy?? water disasotiates to H+ and 0H- if you could take the dissasociated ions away, and combine them how much energy could you get out? In the liquid remaining, more would dissosciate, and the process could be continued. Where does this energy come from - it sounds like free...

I'm searching for a datasheet. This IC device is a two-wire, differental, digital transmitter. Each leg has three output states (hi, lo, gnd). The otputs are differential and trapizoidal in shape. The logo on the chip is a solid white triangle with the point upward. And a Google search...

The 3 pions have different masses and we say this so because of the electro magnetic energy.if this is so then we can never measure a mass because the magnitude of the EM energy that a particle receives depends on the charged particles around it. if you help with this dilemma i would be grateful.

A very interesting article for all. http://www.math.utah.edu/~palais/pi.html Quote from the article: "What really worries me is that the first thing we broadcast to the cosmos to demonstrate our 'intelligence' is 3.14... I am a bit concerned about what the lifeforms who receive it will do...

Recently, a rather large nothing was discovered in the Universe (last August by the University of Minnesota team). This cosmic blank spot has no stray stars, no black holes, not even dark matter, and is a billion light years across. Is there a possibility that this could be the result of a...

Hi all. I can't remember where I saw this but it really confuses me. If x = .999999999... 10x = 9.9999999... 10x - x = 9x x = 1? So does that mean if that .9 recurring is 1 exactly? Thanks for any help.

Hi everyone, Can anybody solve my simple problems of quantum: Usually we say, that wave function Ψ is dependent on r,θ,Φ .But this is just a coordinate system,or more than that. Imagination to this is qite difficult. Moreover somewhere in a book I have read that if Ψ = f(r,θ) exp(imΦ),then on...

Homework Statement We did an experiment in class abvout resistance and temperature. The teacher told us to find out why light bulbs usually blow when you turn on the light. It must be related to the experiment we did which was seeing how resistance changed with temperature Homework...

i got a atronphysics question that i have a hard time to solve it: In the most massive stars, nuclear fusion continues until iron-56 is formed in the core. consider the net process, which is to take 56 hydrogen atoms and turn them into one iron atom. a, how much enegry is released per atom...

Hi, i recently constructed a hofmann apparatus at home out of pvc and had some trouble with it. Basically, once it is set up, i only get gas from one electrode, the other does nothing. H2SO4 is used as the electrolyte, and the is 12 volts at 4 amps being put through it, DC. are there any simple...

ok my doubt is wen i look at a concave mirror(behind focus of mirror) i can see image of my face inverted inside the mirror,,,why does this hapen?? acc to mirror laws i shud get a real image tht too not inside the mirror but outside it! y do i observe an inverted virtual image in case of...

Red light mixed with green light produces yellow light. Yet, a red photon and a green photon don't combine to make a yellow photon (or two of them). Can someone explain this?

Hi there, this is my first ever post in PF. Have you heard of crystal babies? They have been very popular among Taiwan students. And I have googled some information and some people said they consisted of "arcrylate polymers". They also said they are similar to Magic/Crystal Soil. Would...

0.999... = 1 ?? Hey, I was just reading about this and thought it was interesting. Apparently, from what I have read, 0.999... = 1 (where the 999... represent an infinite series of 9's) There were a few good arguments for this 'fact' and also a few arguments against it... What I...

The origin of the Huns is a mystery and subject of much debate. They originated in the Steppes of Central Asia as did other groups. There is evidence that they are a Turkic or proto-Turkic group. The Chinese (Qin) referred to Hsiung-nu (Xiongnu), and some/many consider this an early reference...