Sunday
September 21, 2014

# Posts by Derek

Total # Posts: 242

Physics
0.17 kg point mass moving on a frictionless horizontal surface is attached to a rubber band whose other end is fixed at point P. The rubber band exerts a force F = bx toward P, where x is the length of the rubber band and b is an unknown constant. The mass moves along the ...
November 3, 2010

AP Chem
Pretend you are a nuclear scientist and try to answer this bonus question. Uranium -235 (235U) is used as a fuel in nuclear power plants. However, natural uranium contains mostly U -238 (238U) and very little uranium -235. Therefore, it is necessary that the natural uranium be...
November 1, 2010

can someone please help me! my test is on tuesday on this stuff and this is the one question that I am confused about!
October 30, 2010

Pretend you are a nuclear scientist and try to answer this bonus question. Uranium -235 (235U) is used as a fuel in nuclear power plants. However, natural uranium contains mostly U -238 (238U) and very little uranium -235. Therefore, it is necessary that the natural uranium be...
October 30, 2010

physics
What was the initial kinetic energy of the small mass before the collision? What is the kinetic energy of the two-mass combination after the collision?
October 26, 2010

physics
A 1600 kg car travels at a speed of 10.5 m/s. What is its kinetic energy? Assume that air resistance is negligible.
October 24, 2010

physics
can some one help me with coming with a better way to word theses annswers. As the angle increases, what happens to the tension in the string? *the the tension in the string will get tighter or larger for t1 What would you have to do to the angle to make the tension in the ...
October 20, 2010

physics
can some one help me with coming with a better way to word theses annswers. As the angle increases, what happens to the tension in the string? *the the tension in the string will get tighter or larger for t1 What would you have to do to the angle to make the tension in the ...
October 20, 2010

physics
1.If a mass is 15 cm from the axis of rotation and makes 25 revolutions in 10 seconds, what is its speed in m/s? 2.If m = 0.1 kg and the values above still hold, what is the numerical values of the centripetal force?
October 18, 2010

American Corrections
THE OPENING OF EASTERN STATE PENITENTIARY IN 1829 MARKED FULL DEVELOPMENT OF WHAT
October 18, 2010

Mat 126
A community college has 3,000 students and 90 instructors. The college plans that enrollment will be 3,500 next year. How many new instructors should be hired if the college wants to keep the same student to instructor ratio? 13 instructors 15 instructors 105 instructors 77 ...
October 10, 2010

science
Is a wart an example of a papule or a nodule?
September 2, 2010

science
Which of the following groups of tissue types is found in blood vessels? A. Connective, muscle, and nervous tissues B. Muscle and nervous tissues C. Connective, epithelial, and nervous tissues D. Epithelial and muscle tissues I think it's C because I don't remember ...
September 2, 2010

Health
Normal urine is ____, as indicated by its pH value. A) slightly alkaline, B) neutral, C) slightly acidic, D) extremely alkaline Normally I would post what my answer is along with the question but on this one I have NO CLUE! I can't find the answer anywhere.
September 1, 2010

algebra
Draw And Shade a figure that represents 150%.
August 25, 2010

chemistry
How many grams of ammonia are formed when 1.34 grams of nitrogen react with an excess of hydrogen(3 H2 + N2 reacts to form 2 NH3)(Answer to tenths ex. 2.5)?
July 6, 2010

Calculus
Actually he forgot to convert the kpa(1000 * N/m^2) into 1000 * N/cm^2
June 19, 2010

writing skills 1
what is the name of the common error in the sentences
May 25, 2010

religion
what role does religion play in society in North Korea?
May 16, 2010

4/3x+2/3x
April 25, 2010

Physical Science
a player uses a hockey stick to increase the speed of a 0.200 kg hockey puck by 6 m/s in 2 seconds is the acceleration 3 m/s2?
April 14, 2010

math
7[3m-(m+6)] G.T. -6(M-1)
March 21, 2010

Math
Find an equation of a plane through the point (1, 5, 1) which is orthogonal to the line x=3+5t y=5-1t z=-1+4t in which the coefficient of x is 5.
February 1, 2010

maths
iam a common multiple of 3 & 7 my digits have a total of 9
January 24, 2010

Calc
0 and 1
December 2, 2009

Commonly sorry.
November 17, 2009

How does trade and offering cominly diverse choices INCREASE diversity? Thanks Ms.Sue for answering my last question! ^^
November 17, 2009

I don't get what "What message do these 2 sources present about the impact of globalization on identity?" means..
November 17, 2009

English
I want to know all the Rhetorical and Figurative Devices and Examples in the Essay Hidden Lesson by David Suzuki
October 26, 2009

college physics
tsrusjnsrthnb
October 11, 2009

Can anyone help me with these questions? How was the culture of the Baby Boom so different from that of previous generations? Why are members of Generation X frustrated with Baby Boomers? What are some of the important impacts of Generation Y on the economy? What are the main ...
July 6, 2009

Men who are more socially isolated are more likely to abuse their wives than are men who are socially integrated. Can you not do this topic because I just need an example of another topic in the format above.
July 3, 2009

I need help in making a hypothesis statement for a certain topic, I chose at school. Can anyone give me an example of one? Here is the format, my teacher wants: (The - represents the boxes, he put for each) TOPIC: - - OVERVIEW OF TOPIC: A brief description about your topic...
July 3, 2009

Thank you so much, this really helped me a lot.
July 2, 2009

How does Saki in "The image of the lost soul" use descriptions of places to reach desired effect in story? Can anyone tell me how? an example form the text would be helpful
July 2, 2009

Math
find the unit rate for 9.25 for 18 pounds
February 9, 2009

Algebra
Is there really any difference between vertical asympotes and domains in functions? Are they always the same numbers? Thanks
January 22, 2009

algebra
How can you tell whether a function is rational or not? And how do you determine holes of a graph? Thanks!
January 22, 2009

probability and statistics
a set of 10 cards consists of 5 red cards and 5 black cards. the cards are shuffled thoroughly and i choose one at random, observe its color, and replace it in the set. the cards are thouruoghly reshuffled and i again choose a card at random, observe its color and replace it ...
November 24, 2008

Urgent Chemistry!!
1 mol of an ideal gas expands under isothermal conditions (T=298.15K). The initial pressure and volume is 2.00 atm and 1.00L respectively, and the final pressure is 1.00 atm. Find the expansion work. The answer is w = -101.325 J. I am unsure how to get this answer. Can someone...
November 16, 2008

Chemistry
1 mol of an ideal gas expands under isothermal conditions (T=298.15K). The initial pressure and volume is 2.00 atm and 1.00L respectively, and the final pressure is 1.00 atm. Find the expansion work. The answer is w = -101.325 J. I am unsure how to get this answer. Can someone...
November 16, 2008

Chemistry Confusion!
1 mol of an ideal gas expands under isothermal conditions (T=298.15K). The initial pressure and volume is 2.00 atm and 1.00L respectively, and the final pressure is 1.00 atm. Find the expansion work. The answer is  w =  -101.325 J. I am unsure how to get ...
November 15, 2008

college-Intermediate Microeconomics
The Lump Sum Principle In the 1980s Margaret Thatcher was the British Prime Minister. She was very popular and e ective until she pushed for the idea of a so called lump-sum tax. The lump-sum tax is one in which every citizen pays a single xed payment. Consider the ...
October 8, 2008

physics
A ball is thrown vertically upward with an initial speed of 20 m/s. Two seconds later, a stone is thrown vertically (from the same initial height as the ball) with an initial speed of 24 m/s. At what height above the release point will the ball and stone pass each other?
September 16, 2008

math
solve each of the following equations by the square root method and show your work 4x²-20=0
September 7, 2008

math
solve each of the folowing equations by factoring and show your work x²+x²=13x²-36
September 7, 2008

math
September 7, 2008

math
solve each of the folowing equations by factoring and show your work x²+x²=13x²-36
September 7, 2008

math
solve each of the following equations by factoring and show your work 12x² + 15x + 10= -10x -2
September 7, 2008

math
solve each of the following equations by completing the square and show your work x² + 6x + 24=0
September 7, 2008

math
solve each of the following equations by completing the square and show ur work x²-4x=32
September 7, 2008

math
solve each of the following equations by the square root method and show your work (3x + 2)²=8
September 7, 2008

Mason
solve each of the following equations by the square root method and show your work 4x²-20=0
September 7, 2008

URGENT! Last calculus question!
Hey! So, I was wondering if someone could answer this. I am mad studying for my exam and I still have a few questions left that I just don't have time to answer, and the assignment is due tomorrow. Thanks and here is the question: Use calculus and algebraic methods to do a...
July 29, 2008

Calculus (final question I promise)
1. Use calculus and algebraic methods to do a complete analysis (i.e., intercepts, critical points, intervals of increase and decrease, points of inflection, intervals of concavity, local maximum or minimum points) for each of the following functions and then sketch the graph ...
July 28, 2008

Essay
So, what is your question/problem with this?
July 25, 2008

Urgent CALCULUS
So, I haven't posted in a while...but now I am stummped! Only question I can't get today! A team of students seeks to make a flag representing their commitment to the earth. They will be using a green triangle inscribed in a yellow semi-circle. Find the maximum area of...
July 25, 2008

Calc.
What function would have a derivative of ƒ′(x) = 12x2 + 4x − 10? Explain how you arrived at your answer...I believe the answer is this: f(x)=4x^3+2x^2-10x...and I got this using the power rule and multiplying. Thanks.
July 16, 2008

Calc.
How do I deal with square roots and derivatives? Like: f(x)= Sqrtx....the derivative. find
July 16, 2008

Calc.
What is the derivative of this: not sure because of the pi.... f(x)=x^pi Thanls.
July 16, 2008

Calculus
I figured out e but I am confused for the rest of the equation.
July 15, 2008

Calculus
For the decomposition of Carbon 14, find the age of a prehistoric cave painting discovered in the Lascaux Caves in southern France if the amount of Carbon 14 has decayed to 14.29%...again using calculus formulas. Not sure how to use this equation (content section of course ...
July 15, 2008

Calc.
Nvm, I figured this out myself. :)
July 15, 2008

Calc.
My other questions I didn't understand what e was either. My calculator does not allow me to perform the function that you told me. Please further explain.
July 15, 2008

Calc.
Using calculus: If you invest \$5000 compounded continuously at 4% p.a. how much will this investment be worth in 5 years? I am not sure what e is. Should my equation be this: A(t)=Pe^rt A(t)=(5000e^(0.04)(5)) Thanks.
July 15, 2008

Calc.
yes....f(a+h)-fa)/h
July 14, 2008

Calc.
For the function ƒ(x) = x^3 - 8x + 3, calculate where a = 5 and h = 2. Simplify before substitution (the simplifying is where I am having problems...not sure if my answer is right). Thanks. Using the limits equation.
July 14, 2008

Calc.
verify that lim h>0 (e^x+h -e^h)/h=e^x and explain how this illustrates that ƒ′(x) = ln e • ƒ(x) = ƒ(x)... The notes for this section suck big time, so I really don't know where to begin with this. Thanks!
July 14, 2008

Calc.
Determine the interaction of the line of intersection of the planes x + y - z = 1 and 3x + y + z = 3 with the line of intersection of the planes 2x - y + 2z = 4 and 2x + 2y + z = 1.
July 10, 2008

Calc. for Reiny
this can be done by projections of two vector. recall that the scalar projection of vector b on vector a is a∙b/│a│ so let's find a point on the give line, e.g. the point B(6,0,1) (I let t=0) draw a perpendicular from your given point P(1,-5,2) to meet ...
July 10, 2008

Calc.-Blanking!
wait actually I don't think you can do that...but then I have a problem. I am supposed to find the distance of the point to the line or something like that of the point (1,-5,2) and the line r=(6,0,1) + t(3,1,2) but I thought you needed the scalar equation in order to find...
July 9, 2008

Calc.-Blanking!
Wow, so it is late and I can't think! How do I put this into scalar form: r=(6,0,1) + t(3,1,2)? thanks!
July 9, 2008

Calc.
Use normal vectors to determine the intersection, if any, for each of the following groups of three planes. Give a geometric interpretation in each case and the number of solutions for the corresponding linear system of equations. If the planes intersect in a line, determine a...
July 9, 2008

Calc.
Use normal vectors to determine the intersection, if any, for each of the following groups of three planes. Give a geometric interpretation in each case and the number of solutions for the corresponding linear system of equations. If the planes intersect in a line, determine a...
July 9, 2008

Calc.
I am so confused with this last part of the unit! What in the world is going on: Use normal vectors to determine the interaction, if any, for each of the following pairs of planes. Give a geometric interpretation in each case and the number of solutions for the corresponding ...
July 9, 2008

For Everyone on Jiskha
Hey, I just wanted to say a HUGE THANKS to everyone on this website for helping me out so far with calculus. I am actually understanding a lot because of the help I am getting, you are all a really big help. I appreciate it so much thanks!
July 7, 2008

Calc.
I just copied the question as it was...I tried asking a friend and the teacher about k. When I tried to work it out, I assumed that the direction vector was 0, because it was not k+t or any number at all, but I am still unsure. Thanks.
July 7, 2008

Calc.
Determine the value of k so that the line with parametric equations x = 2 + 3t, y = -2 + 5t, z = k is parallel to the plane with equation 4x + 3y – 3z -12 = 0
July 7, 2008

Calc.
An air ambulance is travelling from Barrie to Toronto. Toronto is located 90 km [S5°E] of Barrie. If the wind is blowing from the South with a velocity of 62 km/h, and the plane’s air speed is 375 km/h, what direction must the pilot fly to make it to Toronto? How do I...
July 6, 2008

Summer School Calculus
I don't know how to answer this: A vector can be used to represent the path of a drill tip used to bore a deep mine shaft in Sudbury one quarter of the way to the centre of the Earth. Represent the vector using a directed line segment and Cartesian co-ordinates and ...
July 5, 2008

Calc.
Determine vector, parametric and, if possible, symmetric equations for the line through Q(2, -1, 3) and the mid-point of the line segment from L(3, -2, 5) to M(1, 4, -7). Not sure what to do with the mid-point.
July 4, 2008

Calculus:Help!
Ok, well both sides are equal yes, but you can't actually do what they are asking right? Because you do the brackets first, and a dot product provides a scalar answer, therefore, you can't add a scalar to a vector, because that is meaningless. Is this correct?
July 3, 2008

Calculus:Help!
Verify using an example that a + ( b• c) = (a •b ) +c ? Explain your reasoning. I have been over this a thousand times and I don't understand (the notes I was given online are incorrect so I don't know how to answer this). THANKS!
July 3, 2008

Calculus:Help!
Any ideas on how to solve this: Use a vector solution to show that a scalar equation for the line through the points P1(x1, y1) and P2(x2, y2) is  y-y1/x-x1 = y2-y1/x2-x1? Very confused as to what is meant by this question. Thanks.
July 3, 2008

Calculus
Yup, I got it, it should be r= (-1,4) + (3,-5), tER..yay for me! lol
July 3, 2008

Calculus
I think I found my mistake, I added wrong lol!
July 3, 2008

Calculus
Determine a vector equation for the line through the points (-1, 4) and (2, -1). I said: r= (-1,4) + (4,-5), tER, is that correct?
July 3, 2008

Calculus
So, yet again, I am confused! State whether or not the following statements are true. Justify your reasoning. a). a• ( b+c ) = a• b + a • c b.) a × ( b+c ) = a × b + a × c c.) a × ( b•c ) = a × b • a × c Thanks, again!
July 2, 2008

Calc.
THANKS!!! You ROCK!!!
July 2, 2008

Calculus
Well ok, I am confused as to how to draw the diagram. But firstly, I am not sure if you accounted for this, but if a wind is coming from the South, you drawing it pointing in the North direction, if you are coming from somewhere, it means you are travelling in the opposite ...
July 2, 2008

Calculus
An air ambulance is travelling from Barrie to Toronto. Toronto is located 90 km [S5°E] of Barrie. If the wind is blowing from the South with a velocity of 62 km/h, and the plane’s air speed is 375 km/h, what direction must the pilot fly to make it to Toronto? What on ...
July 2, 2008

Calculus
What does this mean? For any vector Vector a find Vector a × Vector a. Explain why (this is cross product stuff). Thanks
July 1, 2008

Calculus
I don't really understand what you mean, sorry. Can you explain it differently?
June 30, 2008

Calculus
I am asked this: How can you do the cross product of two-dimensional vectors. Well I would have to guess that you just add a 0 in order to follow the cross product method, but this way there is no third component...is this right?
June 30, 2008

Calculus
My logic was this, as stated from a text book, which also showed your way: the projection of vector a onto b is found by (magnitude a)(magnitude b)(vector b) all over (magnitude b)2
June 30, 2008

Dot product
I am sure, because I tried looking at the question again. Because the only thing that would make sense would be if k=2 but there would need to be a negative somewhere. Could be a typo. Thanks!
June 30, 2008

Dot product
I cant get the correct answer and I can't figure out what I am doing wrong. If a=(2,2k) and b=(4,k) are perpendicular, find k. I have worked it out, and I got -2 but it doesn't work when I check it in the original equation. It should be a.b=0 and then plug in the ...
June 30, 2008