Wednesday
April 16, 2014

Posts by LIZ


Total # Posts: 992

free-body diagram help
A 20.0 kg block is being pushed forward on a flat surface with a force of magnitude 45.0 N against a frictional force of 13.0 N To draw this free-body diagram, would I only have the forces mentioned in the question? or would i include the -9.8m/s^2 force of gravity? Also, how ...

Energy question
Your friend comes across a good deal to purchase a gold ring. She asks you for advice for you to test the ring. The ring has a mass of 4.54 g. When you heat the ring with 94.8 J of energy, its temperature rises from 23.0 degrees celsius to 47.5 degrees celsius. Would you advis...

Energy question
how could you determine the efficiency with which the mechanical energy of a pendulum is conserved?

word problem
If equal amounts of heat are added to equal masses of silver and copper, both at the same initial temperature, which will reach the higher final temperature? Explain your answer. The specific heat capacity of silver is 0.235 J/g degree Celsius and that of copper is 0.385 J/g d...

Energy question
thanks a lot! you gave me some good ideas! and i agree with you about the fluorescent light bulbs. They don't last as long as the box says

Energy question
How would a $10.00 compact fluorescent light bulb (15 W) be an overall money saver compared to an incandescent light bulb (60 W) that costs $0.50?

Energy multiple choice question
Which of the following samples has the highest specific heat capacity? a) A 100 kg sample of lead requires 13 000 J to increase its temperature by 1 K b) A 50 g sample of water releases 1050 J as it cools by 5 degree Celsius c) A 2 kg sample of copper receives 2340 J of therma...

Physics Energy
How would a $10.00 compact fluorescent light bulb (15 W) be an overall money saver compared to an incandescent light bulb (60 W) that costs $0.50?

physics
Show that the acceleration is 7.5 m/s2 for a ball that starts from rest and rolls down a ramp and gains a speed of 30 m/s in 4 s

chemistry
Sodium metal adopts a body-centered cubic structure with a density of 0.97g/cm3. A. Use this information and Avogadro's number to estimate the atomic radius of sodium. B. If it didn't react so vigorously, sodium could float on water. Use the answer from part a to estim...

english
May you please edit this essay? Holden Caulfield in “Catcher in the Rye”, seems to be obsessed with mortality and youthful innocence, both of which are embodied in James Castle and Allie Caulfield. Holden demonstrates these infatuations in his conversation with Phoeb...

chemistry
how to calculate the amount of heat in calories absorbed when 50.0 g of water at 20 degrees C spreads over your skin and warms the body temperature, 37 degrees C

Physics
A ball is fastened to one end of a 30cm string, and the other end is held fixed to a support. the ball whirls in a horizontal circle. Find the speed of the ball in its circular path if the string makes an angle of 30 degrees to the vertical.

chemistry
A room contains 48 kg of air. How many KWh of energy are necessary to heat the air in the house from 7oC to 28oC? The heat capacity of air is 1.03 J/goC

Differential Equations
Solve dy/dx = y/(2y-x) using rational substitution (using v=y/x) with the initial condition y(0)=1. I solved this problem and found C (the constant) to be undefined. That is not the correct answer.

Physics
Ohhh I see what I did wrong! Thanks a lot again!

Physics
I was wondering if my answers are correct. 1. A 50kg person is taking a ride on an elevator travelling up at a steady speed of 2.5m/s. Find the time fo the elevator trip if the elevator does 4900 J of work on the person. My answer: First I used the formula f=mg to find the for...

Physics
thanks a lot!

Physics
I was wondering if my answers are correct. Thanks in advance. 1. A boy pushes down on a car rolling horizontally down the road. The boy pushes down vertically with 10N of force as the car rolls 3.0m horizontally. What work is done? my answer: 30 N•m (or would it be -30N&#...

Linear Algebra!
Write in parametric form the equation of the line that is perpendicular to r=(2i + 4j) + (i - 2j)t and goes through (1,0)

Calculus
write and row reduce the augmented matrix to find the general solution: 2x - z = 2 6x + 5y + 3z = 7 2x - y = 4

Calculus
write and row reduce the augmented matrix to find the general solution: x - 2y + 13 = 0 y - 4x = 17

math-advanced functions
on my exam review, i have this question for composition of functions Given f(x)=3x^2+x-1, g(x)=2cos(x), determine the values of x when f(g(x))=1 for 0≤x≤2π.

Algebra
Determine the equation of g(x) that results from translating the function g(x)f(x)=x^2 +3 upward 10 units 1) g(x)=(x+13)^2 2) g(x)= (x+15)^2 3) g(x)= (x+4)^2 -11 4) g(x)= (x+4)^2 +11

Math. I really don't get this question
three circles are manually tangent externally. their centers form a triangle whose sides are of length 8, 9, 13. find the total area of the three circles

Fundamental Theorm of Calculus
Find the average value of f(x)=3x^2-2 x on the interval [3,6]

Fundamental Theorm of Calculus
Use a definite integral to find area of the region under the curve y=7-4x^2 and above the x-axis. Thanks in advance!

Physics
A test tube in a centrifuge is pivoted so that it swings out horizontally as the machine builds up speed. If the bottom of the tube is 165.0 mm from the central spin axis, and if the machine hits 53500 rev/min, what would be the centripetal force exerted on a giant amoeba of m...

physics
A bicyclist traveling at 8 m/s rides around an unbanked curve. The coefficient of friction (is this static or kinetic friction?) between the tires and the road is 0.42. What is the radius of the shortest turn that the bicyclist can safely make?

Math
3x^2

Math
what is the solution of 3x^+27=0

pre-calc
prove or disprove cos(x-y)=cos(x)-cos(y)

Math
You place a mirror on the ground 6 feet from the lamppost. you move back 3 feet and see the top of the lamppost in the mirror. What is the height of the lamppost?

American Government
Legislation whose tangible benefits are targeted solely at a particular legislator's

Calculus-Aproximate Areas
Estimate the area under the graph of f(x)=sin(pix) from x=0 to x=1 using the areas of 3 rectangles of equal width, with heights of the rectangles determined by the height of the curve a a) left endpoint: b) right endpoint:

Calculus-Aproximate Areas
I tried that, and it was incorrect

Calculus-Aproximate Areas
Estimate the area under the graph of f(x)=sin(pix) from x=0 to x=1 using the areas of 3 rectangles of equal width, with heights of the rectangles determined by the height of the curve at a) left endpoint: b) right endpoint:

Calculus-Approximate areas
Estimate the area under the graph of f(x)= x^2 + 3 x from x=1 to x=10 using the areas of 3 rectangles of equal width, with heights of the rectangles determined by the height of the curve at a) left endpoints: b) right endpoints:

Calculus-Newton Method Approximation
Use Newton's method to approximate the positive value of x which satisfies x=2.3cosx Let x0=1 be the initial approximation. Find the next two approximations, x_1 and x2, to four decimal places each.

Calculus-Applied Optimization Problem
The manager of a large apartment complex knows from experience that 100 units will be occupied if the rent is 425 dollars per month. A market survey suggests that, on average, one additional unit will remain vacant for each 9 dollar increase in rent. Similarly, one additional ...

Math
How do I work out:if life expectancy of male is 78.9 and female is 83.6. Life expectancy is % lower than female. What is formula please

Physics
A research balloon of total mass 225 kg is descending vertically with a downward acceleration of 1.4 m/s2. How much ballast must be thrown from the car to give the balloon an upward acceleration equal to 3.6 m/s2, presuming that the upward lift of the balloon does not change.

calculus
relative maxima and relative minima 2x^2+ 4000/x +10

cinquain poem
thanks for your help and advice

cinquain poem
For social studies we had to make our own 4 topic of cinquain poems. I asked some people and not many knew this type of poem, but one person said it all seem good except for the last lines. Do you think I did the format corret? Thanks for your help 1.Homesteaders Brave, Patien...

Math
-10 + 6g = 110

math
I have fewer ones than tens. the value of my tens is 20 what two numbers can I be

Physics
In a vacuum, two particles have charges of q1 and q2, where q1 = +3.8C. They are separated by a distance of 0.37 m, and particle 1 experiences an attractive force of 4.7 N. What is the value of q2, with its sign? Two spherical objects are separated by a distance of 1.45 ×...

cerritos
political culture refers to

Calculus 2
A tank is full of water. Find the work W required to pump the water out of the spout. (Use 9.8 for g and 3.14 for π. If you enter your answer in scientific notation, round the decimal value to two decimal places. Use equivalent rounding if you do not enter your answer in ...

Calculus 2
Use the method of cylindrical shells to find the volume V generated by rotating the region bounded by the given curves about x = 4. y = 3 x^4 y = 0 x = 2

Franklin High
4x - y = 2, 9x - 2y = 8 find solution by substitution method

Calculus help!
Does the limit of xy/(x^2 + y^2) exist as (x,y)--->(0,0)? Why or why not??

Calculus help!
Three forces with magnitudes 75 pound, 100 lb, and 125 pound act on an object at angles of 30 degrees, -45 degrees, and 120 degrees respectively. Find the direction and magnitude of the resultant vector.

Calculus
Describe the surface and give traces: x = y^2 - 4z^2

Calculus-PLZ help!
Given u=3i-2j+k,v=2i-4j-3k, w=-i+2j+2k, 1 Find a unit vector normal to the plane containing v and w. 2 Find the volume of the parallelepiped formed by u, v, and w. 3 Are any of these vectors parallel? Orthogonal? Why or why not?

Find the center (h,k) and radius
Find the center (h,k) and radius r of the circle and then use these to (a) graph the circle and (b) find the intercepts, if any. 3x^2+36x+3y^2=0

Calculus
Describe the following surface and give traces if available. x^(2)-4z^(2)=4

Statistics
You have a ten question multiple choice test in your next class and you did not study at all. Each question has four choices and only one correct answer. You are going to guess on each question. What is the probability that you score at least a 20% on the test.

math
245 = .25x not sure how to do this since I have only learned with ratios

Chemistry II
Arrange the following 0.10M solutions in order of increasing pH: a. Nacl b. NH4CL C. HCL D. NaCH3CO2 e. KOH

College chemistry
The pH of blood is 7.4 and that of saliva is 6.4. what is the difference in pH between these two solutions? How much more Hydronium ion (H3O+) is in the saliva than in the blood. I need a detailed answer with the formulas if you can. I have a hard time with chemestry

Chemistry
Thank you :) this helped a lot!

Chemistry
Can you explain it better we JUST started this section and im having a hard time with knowing what to put where when it comes to the solutions. what is the acid and what is the base

Chemistry
The pK3 of formic acid is 3.75 A)what is the pH of a buffer in which formic acid and sodium formate have equimolar concentration? B)what is the pH of a solution in which the sodium formate is 10M and the formic acid is 1M?

statistics
What is the probability that 10 of 100 apples will be < 130 g? mean=173 std deviation=34?

Science
For an Indian Youth Environment camp essay why should someone be chosen to go?

chemistry
calculate the yield of CO2 if 30.g of C2H6 reacts with 14.0g of O2. Show work

Calculus
Find the arc length of the curve described by the parametric equation over the given interval: x=t^(2) + 1 y=2t - 3 0<t<1

Calculus help!
On what intervals of t is the curve described by the given parametric equation concave up? Concave down? x=t^2; y=t^(3) + 3t I am a bit confused on how to solve this...any help/explanations are welcome!! (& greatly appreciated!)

Calculus
Find the arc length of the curve described by the parametric equation over the given interval: x=t^(2) + 1 y=2t - 3 --> 0<t<1

Calculus
Convert the polar equation to rectangular coordinates: r = 2-cos theta ...and find all points of vertical and horizontal tangency.

Calculus
Find the arc length of the curve described by the parametric equation over the given interval: x=t^(2) + 1 y=2t - 3 ...0 < t < 1

Calculus
On what intervals of t is the curve described by the given parametric equation concave up? Concave down? x=t^2; y=t^(3) + 3t I am a bit confused on how to solve this...any help/explanations are welcome!! (& greatly appreciated!)

Calculus
Convert the curve to an equation in rectangular coordinates: x=(t+2); y=-2sqrt(t)

Parametric Equations
Find the length of the curve over the given interval: x=t+1 y=ln cos(t) for t=0 ---> t=pi/4

calculus
Find the length of the curve over the given interval: x=t+1 y=ln cos(t) for t=0 ---> t=pi/4

Calculus
Convert to a rectangular equation by eliminating the parameter: x=sin(theta) y=(cos theta)^2

Statistics
The Boeing 757-200 ER airliner carries 200 passengers and has doors with a height of 72 inches. Heights of men are normally distributed with a mean of 69 inches and a standard deviation of 2.8 inches. b) assume that half of the 200 passengers are men, what doorway height satis...

Math- Ms Sue can you help
so the volleyball team had a standard deviation 2.39 and a mean of 68.2 ( I messed up when giving you the numbers, there should have been a comma between 69 &70 not a period-giving 10 numbers) The dance team I got 3.05 standard deviation and a mean of 63 So the should the answ...

Math- Ms Sue can you help
so the volleyball team had a standard deviation 2.39 and a mean of 68.2 ( I messed up when giving you the numbers, there should have been a comma between 69 &70 not a period-giving 10 numbers) The dance team I got 3.05 standard deviation and a mean of 63 So the should the answ...

Math-
I didn't do the standard deviation for each one because I didn't know how, can you help?, if not do you have something ( a link to forward me to) so I can review standard deviations. I do appreciate your help.

Math- Ms Sue can you help
Here is the height, in inches, of 10 randomly selected members of the girls' dance team and 10 randomly selected of the girls' volleyball team Based on the interquartile ranges of the two sets of data, which is a reasonable conclusion concerning heights of the players ...

math- Reiny can you help
can you help with the above question

math- please help
Here is the height, in inches, of 10 randomly selected members of the girls' dance team and 10 randomly selected of the girls' volleyball team Based on the interquartile ranges of the two sets of data, which is a reasonable conclusion concerning heights of the players...

math
Here is the height, in inches, of 10 randomly selected members of the girls' dance team and 10 randomly selected of the girls' volleyball team Based on the interquartile ranges of the two sets of data, which is a reasonable conclusion concerning heights of the players ...

7th grade math
A restaurant donates 2 cans of soup to charity for every 9 bowls of soup it sells. The number of cans of soup donated by the restaurant is proportional to the total number of bowls of soup sold. Which equation represents the relationship between b, the number of bowls of soup ...

Public Speaking
For communication to take place, there has to be: A. transmission of the message. B. medium. C. sharing of meaning. D. absence of noise. is it A is incorrect cause that's wat i had i think is B Which is NOT a benefit of studying public speaking? A. Creates good first impre...

Public Speaking
Which is NOT a benefit of studying public speaking? A. Creates good first impression on others B. Communicates competence C. Proves our expertise D. Develops our ability to communicate ideas and message clearly and with impact correct ans: c

Calculus
does the sum 3/(2^(n)-1) converge or diverge? n=1--->infinity

Calculus
Is the series 2/ln(n) convergent or divergent? n=3 to n=infinity

Calculus
Is the series 1/(n(n+1)) convergent? n=2 to n=infinity

math
Find the base of a triangle whose area is 60in squared and whose height is 6 inches I did 1/2 bh=A 60=3b so b=60/3 b=20 then check so A=1/2bh A=1/2(20)6 A=1/2(120) A=60in squared is this correct?

world history
Any ideas to build a hippodrome for a school project

Physics...PLZ!! =)
A conducting rod whose length is 25 cm is placed on a U-shaped metal wire that has a resistance R of 8 Ù. The wire and the rod are in the plane of the paper. A constant magnetic field of strength 0.4 T is applied perpendicular and into the paper. An applied force moves ...

Physics
A 200-loop coil of cross sectional area 8.5 lies in the plane of the paper. Directed out of the plane of the paper is a magnetic field of 0.06 T. The field out of the paper decreases to 0.02 T in 12 milliseconds. (a) What is the magnitude of the change in magnetic flux enclos...

Physics
A 50-cm wire placed in an East-West direction is moved horizontally to the North with a speed of 2 m/s. The Horizontal and Vertical components of the earth's magnetic field at that location are 25 ìT and 50ìT respectively. What is the emf between the ends of ...

chemistry
If 5.30mL of 0.1000 M NaOH solution is needed to just neutralize excess acid after 20.00 mL of 0.1000 M HCl was added to 1.00 g of an antacid, how many moles of acid can the antacid counteract per gram?

math
You must be doing the same worksheet we are doing right now. :) Why can't I do first grade math?

Math
Ha ha ha Steve!! That's about as far as I got too! It was supposed to end up $400. No idea how though.

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