 # s pepperchin

Senior Members

162

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## About s pepperchin

• Rank
Baryon
• Birthday March 14

## Profile Information

• Location
NY, NY
• College Major/Degree
Millersville University B.S. Physics
• Favorite Area of Science
Physics
1. ## Great Science books to read

Bill Bryson's A Short History of Nearly Everything is good also.
2. ## perpetual motion [quick question]

The Earth itself is not a perpetual motion machine for one simple reason, it is always being bombarded with energy from the sun. A perpetual motion machine has zero change in its total energy. This is not true for the Earth.
3. The friction is dependent on the normal force and the force vectors. I always thought that that would explain why the surface area is not a part of the equation.
4. ## Why is it necessary to take worthless liberal arts courses to obtain my A.S.?

Do you discuss only science with everyone you meet and if not what do you discuss with them? I am a physicist and I felt the same way in college, however now that I know a lot of people who are not physicist or even scientist I can use that information to have discussions with them. An example of this is that my fiance is a history teacher and on a few occasions I have been able to offer suggestions for her curriculum based on classes that I took in college. So although you don't like taking the other classes it makes you a well rounded person who people will want to carry on a conversation with.
5. ## Square root, a reply to a thread in physics

you can only say that it is always positive if you take the square root then square it.
6. ## High School Problem?

It is very true. I tutor high school kids in math so I have copies of the textbooks and it is a true theorem.
7. ## High School Problem?

I started out by adding some labels to your diagram. The red letters are the intersection points of the triangle and the circle and the blue letters are variable for the unknown segments. The length of each of the sides are the same since the triangle is an equilateral. $AD = DG = GA = 16$ We will need that later. We will start by solving for W: We can use the theorem that says for two secant lines that intersect outside of a circle the product of the secant line and the exterior segment of one line are equal to the product of the secant line and exterior segment of the other line. $(AH)(AI) = (AC)(AB)$ $(7+w)(w) = (15)(2)$ This gives us:$w=3$ since $v+7+w=16$ $v+7+3=16$ $v=6$ using the same principle as above for the secant lines from the other angles of the triangle we get: $(GH)(GI)=(GF)(GE)$ $(6)(13)=(y)(y+x)$ $y^2 +xy=78$ eqtn 1 and $(DC)(DB)=(DE)(DF)$ $(1)(14)=(z)(z+x)$ $z^2 + xz =14$ eqtn 2 Solving the length of the side $x+y+z=16$ for z $z=16-x-y$ eqtn 3 plug into eqtn 2 $(16-x-y)^2 + x(16-x-y) =14$ gives us $y=10-\frac{x}{2}$ plug this into eqtn 3 $z=16-x-(10-\frac{x}{2})$ $z=16-x-10+\frac{x}{2}$ $z=6-\frac{x}{2}$ plug these eqtns for y into eqtns 1 $y^2 +xy=78$ $(10-\frac{x}{2})^2 +x(10-\frac{x}{2})=78$ gives us $x=2 \sqrt{22}$
8. I use it on a regular basis but mostly for creating graphics. At this point however most of my graphics have been fairly basic. If there are others who are a little more experienced I would be glad to discuss some things with them. There is a mathematica forum however it isn't as nice as here.
9. ## High School Problem?

It is an equilateral triangle but the numbers givin aren't the length of the whole side but rather the length of the part of that side which falls within the circle.
10. ## summation of tensors

I have that book and after looking over that section it apperrs to me that you are on the right track.
11. ## Polarizing light

If you want to do an interesting experiment with polarization, use corn syrup. In one of my lab classes we set a polarizing filter on an overhead projecter, then we poured corn syrup into a shallow glass dish placed on top of the filter, then we would hold the other filter above it and look at the light passing through all three as it is projected on the wall. Ask your teacher about it and maybe he will show you.
12. ## Help with Potential Difference Problem?

Do you mean grounded? If so what is somethings potential difference when it is grounded?
13. C Sharp express is available for download from microsoft. If you are interested in prgramming then you should learn C Sharp. It is easier to use than C. I have been learning C Sharp and I learned a little C a few years ago. C Sharp is easier than C and you can find books that will help you learn it. Try Barnes and Noble or amazon.
14. thanks for catching that.
15. $y=a^x$ as has already been stated $a^x=e^{xlna}$ we can seperate the exponent into $y=e^xe^{lna}$ and we know $e^{lna}=a$ so that makes our equation for y $y=ae^x$ and we know that the derivative of $e^x$ is $e^x$ so that $\frac{dy}{dx}=ae^x$