Physics - February 2007

Two point charges are placed on the x-axis as follows: one positive charge, q_1 = 4.01 nC, is located to the right of the origin at x= 0.202 m, and a second positive charge, q_2 = 4.98 nC, is located to the left of the origin at x= -0.296 m.

What is the total force (magnitude and direction) exerted by these two charges on a negative point charge, q_3 = -5.98 nC, that is placed at the origin?

I think you are supposed to use couloumbs law to calculate the answer. I got 8.35 x 10^-6 C but its wrong for some reason. Please help

2007-02-03 20:40:08 · 2 answers · asked by wtfitsnguyen 2

1. the speed of the waves ?

2. the wavelenght of the waves ?

3. the frequency of the waves ?

2007-02-03 19:19:50 · 3 answers · asked by Anonymous

2007-02-03 19:11:17 · 1 answers · asked by Anonymous

It there specific shape or amount of layers needed to shield a small rare earth magnet? The magnet is about an inch long and .5 inch in diameter. I want the magentic field to only come off one end of the magnet and shield all the other sides. Is this possible?

2007-02-03 19:05:50 · 5 answers · asked by What_a_what 2

Pilots of fighter planes are subjected to large centripetal accelerations during high-speed turns. Because of these accelerations, the pilots are subjected to forces are greater than their body weight, leading to an accumulation of blood in the abdomen and legs. As a result, the brain is starved for blood, and the pilot can ("black out"). To appreciate the forces that a fighter pilot must endure, consider the magnitude of the normal force that the pilot's seat exerts on him at the bottom of a dive. The plane is traveling at 236 m/s on a vertical circle of radius 738 m. Determine the ratio of the normal force to the magnitude of the pilot's weight. For comparison, note that black-out can occur for ratios as small as 2 if the pilot is not wearing an anti-G suit.

My work:

Ratio = FN/W
FN=ma ---> m(v^2/r)
W=mg

so ((mv^2)/r)/(mg) the m's cancel so (236^2)/738/9.8= 7.7009

but that answer wasn't correct. I need help and any help would be appreciated. Thanks.

2007-02-03 18:55:41 · 4 answers · asked by ncg 2

Will it one day be possible? Im no expert on science so dont be judgemental. ANyway I head that if you can get an object to go faster than the speed of light you could time travel. Perhaps?
Now what about that grandfather theory, if thats what its called.( I think the theory is something like this..) If you went back in time and you grandfather got killed or you killed him would you be alive??

If time travel was possible would it even be known to the public or would they keep it a secret? I think they should keep it a secret because if we could all do it then everyones past/present/future would be altered so we would all be essentially living in different dimensions. ?

2007-02-03 18:55:12 · 6 answers · asked by No need to be rude people, dam 1

A satellite is in a circular orbit around an unknown planet. The satellite has a speed of 1.67 x 104 m/s, and the radius of the orbit is 4.39 x 106 m. A second satellite also has a circular orbit around this same planet. The orbit of this second satellite has a radius of 7.98 x 106 m. What is the orbital speed of the second satellite?

My work:
I had some crazy idea that proportions would work

V1/R1= V2/R2 which gave me 30356.7 which was incorrect

I really have no clue on how to approach this problem and any help given would be greatly appreciated. Thanks

2007-02-03 18:44:58 · 3 answers · asked by ncg 2

2007-02-03 18:44:03 · 14 answers · asked by Anonymous

At amusement parks, there is a popular ride where the floor of a rotating cylindrical room falls away, leaving the backs of the riders “plastered” against the wall. Suppose the radius of the room is 3.30 m and the speed of the wall is 10.0 m/s when the floor falls away. (a) How much centripetal force acts on a 55.0-kg rider? (b) What is the minimum coefficient of static friction that must exist between a rider’s back and the wall, if the rider is to remain in place when the floor drops away?
(a) Fc=mv^2/r =(55 kg x (10.0 m/s)^2)/ 3.30m = 1666.67 N

(b) Fc=FMax= usFN = usmg
usmg=mv^2/r
us=(((55kg) (10)^2)/ (3.3))/ (55) (9.8) = 3.09

I really need help on part b. Thanks in advance.

2007-02-03 18:32:15 · 2 answers · asked by ncg 2

I am working on an open-source audio compression program and am trying to find a way to efficiently minimize the amplitude of a wave file, both for compression purposes and to make sounds modified with it put less stress on speakers.

Here's my mathematical dillemma:

Supposed you have two frequencies that last for about 1/10th of a second (IE a 2048 sample FFT window)...and you want to modify every other frequency to be rotated a certain amount of phase from the last frequency.
You are given first frequency is f1, second (f2) and magnitudes m1 and m2 to form an optimization equation that defines what phase relative phase angle (-180 to 180 degrees) would each phase START at relative to the other to minimize the peak amplitude of the combined signals.
As a precondition, though, the phasing should not reduce audibility of each frequency (IE no significant phase cancellation...at least to the point the human ear can hear both frequencies clearly)

2007-02-03 17:49:31 · 2 answers · asked by M S 5

Please justify well.

2007-02-03 17:49:26 · 4 answers · asked by Leo 2

Please justify well.

2007-02-03 17:48:29 · 4 answers · asked by Leo 2

Help! I need to know why a compound microscope inverts an image seen through the lens (so that if you move the object left it appears to go right) and why a stereoscopic microscope (also called large-object view microscope, at least by my professor) does not do this (hence when the object is moved lieft it appears to move left through the lens as well). Thanks!

2007-02-03 17:45:13 · 1 answers · asked by Anonymous

Ive been working on this for a while and I cant seem to get the right answer:

A 100 W incandescent light bulb converts approximately 2.5% of the electrical energy supplied to it into visible light. Assume that the average wavelength of the emitted light is λ = 540 nm, and that the light is radiated uniformily in all directions.
How many photons per second, N, would enter an aperture of area A = 8 cm2 located a distance D = 5 m from the light bulb?

Ive determined that each photon has 2.3eV of energy, but I cant find the intensity

2007-02-03 17:18:23 · 1 answers · asked by Anonymous

2007-02-03 17:13:05 · 2 answers · asked by Anonymous

Acording to the bigbang the universe evolved from a small point which erupted and created the space time contininum at the time of eruption I suppose the point was rotating rapidly because we are all rotating about somethig and this blast nade the matter split up Now imagine this i have made a small ball with a han full of mud and i place it on the ground and rotate it in hthe process of rotation the mud will be splited up from the ball unformly and at last after the ball is all gone i see a disc of mud so my question is why are galaxies in different shapes but not only disc shaped and spiral. I will also be pleased if you would answer for this Why does a body tend to rotate.

2007-02-03 16:51:11 · 6 answers · asked by josyula 2

Using the fact that acceleration is the second derivative of position, find the acceleration of the block as a function of time.

Express your answer in terms of w, t, and x(t).

I'm having troubles with many of these types of problems....can anyone help?

2007-02-03 16:49:48 · 1 answers · asked by Anonymous

First of all, I don't have much electronics experience apart from doing a semester of electronics in yr 12 (and they didn't really teach us how any of it works, just said 'put this resistor here and that there' etc).

I pulled 3 LED's out of a pc which my neighbour was going to throw out, so I don't really know what the voltage range is.. (If that makes it impossible to use them, please tell me which ones to buy because I still want to do the following)
Now, I want to use them in a craft project and I don't have a clue how to hook them up properly. It doesn't really matter to me whether I hook them up to a battery or a power point, but I'm on a low budget so I figure battery would be cheaper, right?

Now, how on earth do I go about making the circuit board for them? Do I need to make a proper circuit board at all (I don't have that liquid for getting the copper off etc)? All I want is for those three LED's to be lit up solid.

2007-02-03 16:35:49 · 3 answers · asked by Pietzki 3

If time goes on for billions of years more, and space has trillions of stars that could support habitable planets, the probablility of discovering time travel at some point in the future goes up. It would seem like we should be seeing thousands of visitors from the future given these odds. Maybe this means there is no future.

2007-02-03 16:17:12 · 9 answers · asked by Zefram 2

I propose this as a great way to dispose of annoying pests - would he be a good replacement for uranium ?

2007-02-03 16:12:44 · 4 answers · asked by Angela 2

it is based on gravitation?

2007-02-03 16:06:30 · 3 answers · asked by Anonymous

2007-02-03 16:05:47 · 9 answers · asked by Suresh 1

2007-02-03 15:50:20 · 15 answers · asked by naveed 1

2007-02-03 15:46:52 · 5 answers · asked by naveed 1

2007-02-03 15:44:34 · 5 answers · asked by naveed 1

If something was infinitely big and it began to shrink, no matter how fast or how long for it would always be INFINITELY big because infinity has no end. I have read on numerous occasions that before the big bang, the universe was 'infinitely' small. but surely if this was the case it would take an infinite amount of time for it to expand (or explode) into something even the size of an atom. considering there is a finite amount of matter in the universe, surely it was finitely small.

2007-02-03 15:30:14 · 11 answers · asked by Jamin 2

The average human body temperature is 98.6 degress F. what is the equivalent temperture on the celcius scale?
____c

2007-02-03 15:09:18 · 10 answers · asked by Hey ;) 3

T requires that all motions be continuous, then it cannot be a natural motion for a body to be at two distinct places at two different times but at no intermediate place during that interval. If this is correct Does it change any of the properties of L`?

2007-02-03 14:51:37 · 2 answers · asked by Anonymous

2007-02-03 14:30:15 · 2 answers · asked by beboe007 1

Water at 2°C is heavier than water at 5°C?
A pulley with 3 strings could have more M.A. than one with 4?

2007-02-03 13:55:55 · 9 answers · asked by ghettoco 1