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As implied by YT's link, this subculture appears to stem from the African American/hip-hop culture. In my opinion, it's a degenerative subculture that has nothing worthwhile to offer to society. The culture, of course, originates in the U.S., and it makes me wonder how an educated society allows people to develop such a lacking culture. If we think back to the Civil War period, we realize that African Americans were released into society with little to no education. The rest of society continued to section them off for the next 100 years, and neglected their societal and educational needs- the kind of needs that would allow them to function properly with the rest of American society. But they didn't get the attention they needed, and thus began to form their own culture and subcultures. I blame the leaders in America for not having the foresight to prevent these types of unprogressive and derogatory subcultures. And its unfortunate that its worked its way into educated societies, both in America and in other parts of the world.

I see, that makes more sense, thank you

First off, I appreciate the replies above I have a question about uniform circular motion. I was wondering to myself whether I could calculate the period of the Earths rotation from the mass of an object on Earth. I was using Newtons Universal Law of Gravitation for the centripetal force acting on the mass and the other basic equations involving tangential velocity, radius, and period. I kept getting strange numbers for my answer, nothing close to the period of the Earths rotation, and my reasoning is this: I cannot calculate the period of the Earths rotation by using an object of mass that exists on the Earth because it is not the rotation of the Earth that pulls us toward its center. The gravitation field is what keeps us attracted to earth, and even though the Earth rotates, the centripetal force that acts on the objects on earth is negligible. Is my reasoning correct?

Well I've been reading about it a little more, and from what I see, distilled water appears to be the purest. I read one case where someone had gotten sick from glacier water because the water contained "black plant material." If I recall correctly,the distilling process involves vaporizing the water to separate it from heavier materials, and of course the water has to be boiled in the process, so common sense would tell me that the process would also kill off any bacteria in the water.

I can understand scalars and vectors being simple concepts if you're simply considering a value and a direction, respectively. But its been my experience that they require more thought when you start considering projections, bases, norms, etc. I wouldnt think that anyone here is trying to pick a fight, but as a physics major I've noted the importance of precision, which is what I believe swansont was getting at.

Thanks for the article, thats a little more comforting. The guest I spoke of also mentioned that glacier water is the best because its not distilled or messed with in any fashion by the bottling companies. So I suppose the combination buying glacier water and keeping it stored in a cool place will limit my intake of the phthalates and other unwanted additives. I'm still curious if boiling the water would get rid of any phthalates already in the water...

I'm no fan of Joe Scarborough but what's wrong with believing Bush to be an idiot, or that the war in Iraq is for the most part senseless?

I was listening to a radio show a few weeks ago, and they had a guest by the name of Sydney Ross Singer, who is a "medical anthropologist." He discussed many things about humanities current culture that could be making people sick. He mostly discussed how women's braziers have been linked to breast cancer, which I found interesting. But he mentioned something in passing about bottled water, which is that plastic bottles contribute hazardous materials ("carcinogens" was the word he used I believe). He said that he called the FDA, and they told him that the plastic is actually consdiered a food additive. This is his site: selfstudycenter.org. Then a few days ago, the same show had a guest talking about bottled water specifically. He's an investigative reporter by the name of Randall Fitzgerald, and this is his site: http://hundredyearlie.com. He had quite a bit to say about bottled water, so I wont list everything he said, but he stated that the chemicals that are used to make the plastic bottle flexible, migrate into the water, usually at room temperature. I'm curious what your scientific opinions may be on this matter, or even your speculation. I drink alot of bottled water, so if this is true, I'm curious if theres any way to purify the water. For instance, if I boil the water before I drink it, will that get rid of any hazardous chemicals that may be in the water?

Ok, here are the other questions I'm stuck on... 1. An airplane is flying with a velocity of 240 m/s at an angle of 30 degrees with the horizonal. When the altitude of the plane is 2.4 km, a flare is released from the plane. The flare hits the target on the ground. What is the angle theta? And the book has this drawing: So I used the equation [math]y= v_0y*t + (1/2)*a_y*t^2[/math] to get [math]-2400 = (240*sin(30))*t - 4.9*t^2[/math]. Sovling for t I get 37.5 degrees. I multiply t times (240*cos(30)) to get the x-distance, which I think will give me the length of the the hypotenuse. knowing the length of these two sides, I find the angle to be 17 degrees, which is wrong. The answer is 42 degrees. I think I'm using the wrong angle of 30 degrees, but I dont know. 2. A police car is traveling at a velocity of 18.0 m/s due north, when a car speeds by at a constant velocity of 42.0 m/s dur north. After a reaction time of .800 s, the policeman begins to pursue the speeder at an acceleration of 5 .00 m/s^2. Including the reaction time, how long does it take for the policeman to catch up with the speeder? I used the eq. [math]y= v_0y*t + (1/2)*a_y*t^2[/math] for both the policeman and the speeder, and set them equal to eachother, because I figure that their distances have to equal eachother when the cop catches up to the speeder. So I have [math]18*t + 2.5*t^2 = 42*t[/math], and I solved for t to get 9.6 s. The 9.6 plus the reaction time would give me 10.4 s. The answer is supposed to be 11.1 s. 3. A duck has a mass of 2.5 kg. As the duck paddles, a force of .10 N acts on it in a direction due east. In addition, the current of the water exerts a force of .20 N in a direction of 52 degrees south of east. When these forces begin to act, the velocity of the duck is .11 m/s in a direction due east. Fine the magnitude and direction (relative to due east) of the displacement that the duck undergoes in 3.0 s while the forces are acting. Here I found the x and y component forces first. In the x-direction, .10 N from the paddling, and .20*cos(52) from the wind, added together it gives .223 N. In the y-direction, theres only a force of -.20*sin(52), which gives -.158 N. Adding the two forces squared and taking the root to get the net force, I have .273 N. To get the acceleration, I divide that by the ducks mass to get .109 m/s^2. Then I have [math] x= v_0x*t + (1/2)*a_x*t^2= .11*3 + .5*.109*9= .82 m[/math]. The book has .78 m. Lastly... 4. A person has a chioce of either pushing or pulling a sled at a constant velocity, as the drawing illustrates. Friction is present. If the angle theta is the same in both cases, does it require less force to push or pull? The book has this picture: I would think that it would take less force to pull the sled, because the y-component from the pushing is just pointing into the ground, but I'm not sure. @ D H Thanks for the reply. So are you saying that the shuttle wouldn't be able to move at a constant velocity? I'm still wondering in the case of the sled being pulled at a constant velocity if it is the kinetic friction that causes there to be no net force...Does no net force always mean that the forces acting on an object are balanced out?

Well, I've come upon a few more problems, any help is appreciated. I wanted to ask how something can move at a constant velocity, and have no net force acting upon it. If the object is still, it makes sense, but if someone is draging a sled for instance at a constant velocity, how do the forces balance out to give zero net force? I assume kinetic friction plays a role in that, but what if the space shuttle is moving through space at a constant velocity, what cancels out the thrust such that it would not accelerate? I'll post the other problems later, thanks for any help...

Ok, I got it. I see that the initial speeds are the same. Thank you

I did, I just have very little experience with physics. Another problem: A cannon shoots a ball at 45 degrees from the horizontal. The ball travels 80 miles and hits with the same vertical speed that it had when it left the cannon. Find the time interval and the initial velocity. I have that [math]a_x=0[/math], [math]x=1.3E5m[/math], and the initial speed of the ball in the y-direction is equal to the final speed in the y-direction. Every time I plug the numbers into the kinematics eq.'s I still have two unknowns. I'm not sure where to go from here.

Yep, I did. Sometimes my book is wrong so its hard to know if its me or the book, lol. But thanks again for your help

Ah ok, I see where I went wrong. I was using the x distance for figuing out the time instead of the y distance. Thanks for everyones help.

I got that t=2s, and x=20m, so v-initial would be 10 m/s. The books answer is 36.1 m/s. I'm not sure where I went wrong.

I'm not sure what that infers. No acceleration in the x direction?

After its been thrown, none i think....

Well, I have all summer to prepare for calculus based physics in the fall. I started last night and I've already come upon a problem. I'll just use this thread to ask questions instead of making 100 of them throughout the summer. Any help is appreciated. The problem is: A man throws a ball horizontally such that the ball leaves 1.5m above the ground. At what velocity must the ball leave his hand so that it reaches a point 20m away without touching the ground before it gets to that point? I got that the initial velocity in the y-direction is 0, which allowed me to find t. But that still leaves acceleration in the x direction and initial velocity in the x direction to be accounted for. I'm not sure where to go from here.

The example looks fine to me. Definitions and notation can get a bit tricky tho'.

A big M stands for molarity, a lower case-cursive m stands for molality. In the case of M(1)*V(1) = M(2)*V(2), we're dealing with molarity. Molality is moles of solute per kg of solvent, very different from molarity.

Yeah you're right. Now I remember you can use the equilibrium equation for gases as long as their concentrations are in atm's.

I know some gases, if not most, do. Like HCl bubbled through water gives HCl(aq), which isn't a pure solid or liquid, thus its addition would cause the reaction to shift. If I recall right, I believe some gases are more soluble than others. Something to do with the polarity of the gas molecules.

Pure solids and liquids have an activity (or in this case a concentration) of 1, so it doesn't matter how much of the solid you add because its coresponding value in the equilibrium constant equation will always be 1. H(+)aq on the other hand is not a pure solid or liquid, thus an increase or decrease in its concentration can cause a shift.

Yeah, I see what I did wrong. I should have divided by the norms instead. Thanks for the replies

If I have z= ||v||u + ||u||v, can I say that (z/uv) = (||v||/v) + (||u||/u) ?