Tuesday
September 23, 2014

Posts by john


Total # Posts: 6,249

Statistics
Which of the following statements about the correlation coefficient r are true? I. It is not affected by changes in the measurement units of the variables. II. It is not affected by which variable is called x and which is called y. III. It is not affected by extreme values. I ...
November 12, 2012

Statistics
Suppose a study finds that the correlation coefficient relating family income and SAT scores is r = +0.98. Which of the following are proper conclusions? I. Poverty causes low SAT scores II. Wealth causes high SAT scores III. There is a very strong association between family ...
November 12, 2012

math
Q) (Speed) Ahmed drives from Abu Dhabi to Dubai. The journey takes him 1 hour 30min and the distance covered is 130km. What is the average speed at which he was travelling (rounded to the nearest 1km/hr)?
November 12, 2012

science
What is meant by depassivation of reinforcement? State the two main chemical attacks that lead to depassivation
November 11, 2012

Physics
A file cabinet weighing 1500 N is at rest on the floor. The coefficient of static friction between the floor and the cabinet is 0.5. What is the minimum force required to make the file cabinet move horizontally
November 10, 2012

science
Abiotic factors
November 10, 2012

math
how do you go about doing place value puzzles .can you show me an example please(hundredths place,thousandths place,ones place and tenths place
November 9, 2012

physis
45
November 9, 2012

Math
113.50 ? 114.50 ? 115.00
November 8, 2012

physics
A shopper in a supermarket pushes a loaded 32 kg cart with a horizontal force of 15 N. The acceleration of gravity is 9.81 m/s2 . a) Disregarding friction, how far will the cart move in 3.3 s, starting from rest? Answer in units of m
November 8, 2012

Organic chemistry
Help me find my percent yield for my witting reaction experiment.... The weight of my final product was: 0.13 I put 0.40 g of benzyltriphenylphosphonium chloride, 0.23 g of 9-anthraldehyde and 1.0ml DMF and 0.5ml of aqueous sodium hydroxide into the flask at the start of the ...
November 8, 2012

Chemistry
Help me find my percent yield for my witting reaction experiment.... The weight of my final product was: 0.13 I put 0.40 g of benzyltriphenylphosphonium chloride, 0.23 g of 9-anthraldehyde and 1.0ml DMF and 0.5ml of aqueous sodium hydroxide into the flask at the start of the ...
November 8, 2012

Organic Chemistry
chlorobutane, chloride ion is weaker leaving group
November 8, 2012

Statistics
Suppose the correlation between two variables is -0.57. If each of the y-values is multiplied by -1, which of the following is true about the new scatterplot? It slopes up to the right, and the correlation is -0.57 It slopes up to the right, and the correlation is +0.57 It ...
November 8, 2012

Statistics
New York and Pennsylvania have progressive toll roads. Upon entering the toll road the driver receives a ticket marking the location and time of entrance. Upon exiting the mileage is computed and the driver pays the toll. Which of the following would you expect to be true ...
November 8, 2012

science
Assume an average human cell has a cell cycle of 20 hours. Calculate how many cells there would be after 80 hours.
November 7, 2012

social studies
what resources did early native american used
November 7, 2012

Physics
A freight train has a mass of 1.7 × 10^7 kg. If the locomotive can exert a constant pull of 5.2 × 10^5 N, how long would it take to increase the speed of the train from rest to 74.6 km/h? Disregard friction. Answer in units of s
November 7, 2012

fractions from least to greatest
can you list 3/4, 3/5, and 5/6 from least to greatest
November 7, 2012

History,Art
Yes I have, I need to provide information about her and her life but I need to know her name.
November 7, 2012

History,Art
I need to find a picture of 2 paintings: Crimson Rambler by Philip Hale and Automat by Edward Hopper. I also need some assistance with this assignment involving these two paintings. I have to outline a story I would write about the woman in the paintings(I'm supposed to ...
November 7, 2012

Pre Calc
How to prove tan4x = 1-8 sin squared of cos squared of x
November 6, 2012

chemistry
Sodium sulfate is slowly added to a solution containing 0.0500 M Ca2 (aq) and 0.0230 M Ag (aq). What will be the concentration of Ca2 (aq) when Ag2SO4(s) begins to precipitate? What percentage of the Ca2 (aq) can be separated from the Ag (aq) by selective precipitation?
November 5, 2012

grammar
SSS means a compound subject and PPP means a compound predicate if i am right .(1) Blue flages and green rushes grew along the river.I underline blue flags and green rushes once,and grew along bthe river. twice.(2)I underline the flat creek bed once and was made of warm, soft ...
November 5, 2012

grammar
can you underline the complete subject and the complete predicate of these sentences.show by stating (SSS)and(PPP)also.(1)Blue flags and green rushes grew along the river.(2)The flat creek bed was made of warm ,soft mud. (3)Laura hopped and splashed in the cool creek.(4)The ...
November 5, 2012

Math
10/12=x/36 360/12=30 yds 1296 inches converted into yards is 36 yds
November 5, 2012

Statistics
A random sample of 250 men yielded 175 who said they'd ridden a motorcycle at some time in their lives, while a similar sample of 215 women yielded only 43 that had done so. Find a 99% confidence interval for the difference between the proportions of men and women who have...
November 5, 2012

Statistics
@MathGuru you're useless. You only solve the obvious and then leave us hanging.
November 5, 2012

Statistics
A random sample of 384 people in Dalto City, a mid-sized city, revealed 112 individuals who work at more than one job. A second random sample of 432 workers from East Dettweiler, another mid-sized city, found 91 people who work at more than one job. To conduct a significance ...
November 5, 2012

biology
In which sequence did aerobes, anaerobes, chemolithotrophs and cyanobacteria evolve? What evidence is there to support your answer. If someone can answer please. I think its talk about how cyanbactoria evolve.
November 4, 2012

statistics
A random sample of 250 men yielded 175 who said they'd ridden a motorcycle at some time in their lives, while a similar sample of 215 women yielded only 43 that had done so. Find a 99% confidence interval for the difference between the proportions of men and women who have...
November 4, 2012

statistics
A random sample of 384 people in Dalto City, a mid-sized city, revealed 112 individuals who work at more than one job. A second random sample of 432 workers from East Dettweiler, another mid-sized city, found 91 people who work at more than one job. To conduct a significance ...
November 4, 2012

Maths
Let f(x) = tan(x). What is the formula for the conditioning number of f? Evaluate this formula for x =(π/4), 1.01, 1.26, 1.51 (in radians, working to 3 signifi cant figures, the precision that is implicit in this data). Replace each of the expressions for x by its ...
November 4, 2012

Physics
Hmm this is probably wrong but I was thinking of something like this: M1 = the mass that was in one of the holes R2 = the radius of one of the holes M = mass of the whole original disk R = radius of whole original disk I think the following relation makes sense: M1(R/2)^2 = 0....
November 2, 2012

Physics
No problem. For my question, I know the goal is to basically subtract the inertia's of the 3 holes from the whole disk's inertia, 0.5*MR^2, but I think what I'm stuck on is how to find that value, or relate it to what we know. The final inertia needs to be 0.81(0.5...
November 2, 2012

Physics
To reduce its rotational inertia, an engineer proposes drilling three holes in a large wheel of radius R. The holes are to be centered midway between the center and edge of the wheel. What should be their radii (in terms of R) if drilling the holes is to reduce the rotational ...
November 2, 2012

trig
2 cos(theta-13)= square root of 3
November 2, 2012

maths
a multiply b =12 b multiply c=13 c multiply d=14 what is the answer for abcd=???
November 2, 2012

Calculus
Find the volume of the solid obtained by rotating the region enclosed by y=x^3, y=25x, x ≥ 0
November 1, 2012

Calculus
Find the volume of the solid obtained by rotating the region enclosed by y=x^3, y=25x, x ≥ 0
November 1, 2012

science
What volume of a 6.0 M NaOH solution would you need to prepare 250.0 milliliters of a 3.0 M NaOH solution?
November 1, 2012

statistic
in a random sample of 400 voter, 120 plan to vote for candidate A. determine a 95% confidence interval
November 1, 2012

Physics
Which of the following equations describes the condition for observing the fourth bright fringe in Young's double-slit interference pattern? Assume n = 0 for the central bright fringe. d sinθ = λ d sinθ = 3λ/2 d sinθ = 3λ d sinθ = 4λ
October 31, 2012

Physics
What is the critical angle of light traveling from benzene (n=1.501) into air? 40.05o 48.22o 41.78o 62.63o
October 31, 2012

Physics, newtons laws
Let L=length of string=120cm Tsin(a)=mv^2/R, R=Lsin(a), T=mg/cos(a) mgtan(a)=mv^2/Lsin(a), mgsin^2(a)=mv^2cos(a)/L, g(1-cos^2(a))=v^2/L (cos(a)) gLcos^2(a)+v^2cos(a)-gL=0 let x=cos(a), use quadratic formula to solve for x x= (-v^2+sqrt(v^2+4L^2*g^2))/2Lg a=acos(x)=25 degrees
October 29, 2012

geology
what is the Sample Locality Age (Million years)in Granite: Scottish Highlands, Gabbro: Sudbury Canada and Gneiss: Greenland?
October 27, 2012

physics
Suppose you waik 18.0m straight west and then 25.o m straight north. How far are you from your starting point and what is the compass direction of a line connecting your starting point to yourfinal position?
October 25, 2012

science
10.6
October 24, 2012

science
How tall is the tree if the sun is at a 53° angle above the horizon and the shadow is 8.0 meters long?
October 24, 2012

Calculus
A baseball diamond is a 90 foot square with the pitcher's mound at the square's center. A runner races for home at 25 ft/sec. How fast is his distance from the pitcher changing as he crosses the plate?
October 24, 2012

Algebra (Graphing Functions)
Actually I figured it out.
October 24, 2012

Algebra (Graphing Functions)
Consider the following function. f(x) = −3x if x < −2 x2 if −2 ≤ x < 2 −3 if x ≥ 2 Please help me find the intervals on which f is increasing, is decreasing, or is constant(in interval notation). As well as the x and y intercepts for ...
October 24, 2012

literature
Reflecting on this week’s literary readings, as well as your own reading experiences, identify at least one major similarity and one major difference between the forms of the short story and the poem. How do the differences between these literary forms affect how you read...
October 24, 2012

physics
A ball is attached to one end of a wire, the other end being fastened to the ceiling. The wire is held horizontal, and the ball is released from rest (see the drawing). It swings downward and strikes a block initially at rest on a horizontal frictionless surface. Air ...
October 23, 2012

Boolean algebra
Simplify this function using Boolean algebra laws? I am stuck on this part of my homework (x2'x1'x0') + (x2'x1x0) + (x2x1x0') I know you have to use distributive laws to do this. Any help is appreciated. Thank you.
October 23, 2012

ict
I need help woth my cross word
October 23, 2012

Physics
The wheel is attached to an electric generator and the rotation rate drops from 290 to 230 in 3.5 . What is the average power output?
October 23, 2012

Physics
Find the energy stored in the solid flywheel of mass 8.0×104 and radius 1.8 when it's rotating at 290
October 23, 2012

Math
Monday, Mr. C stacked a display case of 80 heads of lettuce. By end of day, some were sold. Tuesday Mr. C counted lettuce left and decided to add an equal number of lettuce (**hint - he doubled the leftovers).  At end of Tuesday, he sold the same number as ...
October 22, 2012

chemistry
oh alright thank you i found out my mistake. thank you sir.
October 22, 2012

chemistry
Will a fluoride concentration of 1.0 mg/L be soluble in a water containing 200 mg/L of calcium? I got Qsp 1.38 * 10^-8 and Ksp = 3.45*10^-11 does that seem right? and does this mean fluride concentration will be soluble in water containing calcium?
October 22, 2012

chemistry
thank you sir.
October 21, 2012

chemistry
Will a fluoride concentration of 1.0 mg/L be soluble in a water containing 200 mg/L of calcium? This is what i found for ksp CaF2<--> Ca(2+) +2F(-) Ksp=(x)(4x^2) where x=solubility Therefore, Ksp=3.7 x 10^-11 and for Qsp I am not sure how to go on about calculating that.
October 21, 2012

Physics
A 45-kg skater rounds a 5.0-m radius turn at 6.3 m/s. (A.) What are the vertical and horizontal components of the force the ice exerts on her skate blades? (B.) At what angle can she lean without falling over?
October 21, 2012

Cemistry
This is what i found for ksp CaF2<--> Ca(2+) +2F(-) Ksp=(x)(4x^2) where x=solubility Therefore, Ksp=3.7 x 10^-11 and for Qsp I am not sure how to go on about calculating that.
October 21, 2012

Cemistry
Will a fluoride concentration of 1.0 mg/L be soluble in a water containing 200 mg/L of calcium?
October 21, 2012

Algebra 2
x = 0 and x = 3 you did it right.
October 21, 2012

math
christi rides her bicycle 7 blocks south. 3 blocks east, 5 blocks north, and 8 blocks west. how many blocks has she ridden when she crosses her own path
October 20, 2012

math
You worked from 2:30pm – 8:45pm with a ½ hour lunch break. Your hourly wage is $7.50/ hour. How much did you earn?
October 18, 2012

chemistry
a.) The simultaneous oxidation and reduction of a chlorite ion 3ClO-2(aq)-><-2ClO-3(aq) + Cl-(aq. b.) IO-3(aq) + 6OH-(aq) + Cl(aq)-><-IO-5,6(aq) + 3H2O(i).
October 18, 2012

chemistry
write equilibrium constant expression for each reaction. a) The oxidation of ammonia with CIF3 in a rocket motor NH3(g) + CIF(g)-><-3HF(g) + 1/2N2 + 1/2Cl(g) b.) The simultaneous oxidation and reduction of a chlorite ion. 3Cl-2(aq)-><-2ClO-3(aq) + Cl-(aq) c.) IO-3(...
October 18, 2012

Math
Suppose you draw 5 cards out of a deck of 52 and get 2 spades and 3 hearts. What is the probability that the first card drawn was a spade?
October 17, 2012

physics
a baseball is thrown horizontally at a velocity of 35 m/s from a height of 1.5 m. How long does it take to hit the ground? how far does it travel?
October 17, 2012

Math
simple. Set up two fractions like so: 159mi/5.3gal =x/1gal answer would be 30 miles.
October 17, 2012

chemistry .chemistry
obtanin a piece of comcentrated acetic acid and 10 ml of di- water . bring the content of this beaker to a gentle boil using a low flame on the Bunsen burner . boild for about 3minutes , alow to cool and then remove the steel wool ball . what is formula? Ans : Fe + 2CH3COOH...
October 17, 2012

chemistry
obtanin a piece of comcentrated acetic acid and 10 ml of di- water . bring the content of this beaker to a gentle boil using a low flame on the Bunsen burner . boild for about 3minutes , alow to cool and then remove the steel wool ball . what's happened in procedure? i ...
October 16, 2012

chemistry
thank you
October 16, 2012

chemistry
From which sublevel are the first 2 electrons for Fe removed from ______ From which sublevel is the next electron for Fe removed from _________ Why does the removal of electrons stop at this subleval and number of electron?? Please help me !!!
October 16, 2012

chemistry --
What determines whether 2 or 3 electrons will be removed from Fe when it reacts with another chemical or element?
October 16, 2012

math
The value of a new car decreases exponentially.Suppose your mother buys a new car for 22,000. The value of the car decreases by 20% each year. a.what is the initial price of the car. The decay factor. b. write an equation to model the value of the cars years after she buys it...
October 14, 2012

chemistry
compare the emission color of lithium to that of potassium .what can you conclude about these two elements and the energy levels that their electron transition?
October 12, 2012

English
...
October 11, 2012

chemistry
How do you convert that to kJ/mol
October 10, 2012

Repost-Physics 1
A crate of mass 48 kg is pushed up a frictionless ramp by a person as shown in the figure below. Calculate the work done by the person in pushing the crate a distance of 11 m as measured along the ramp. Assume the crate moves at constant velocity. _____J
October 9, 2012

Repost-Physics 1
Two railroad cars, each of mass 2.2 104 kg, are connected by a cable to each other, and the car in front is connected by a cable to the engine as shown in the figure below. The cars start from rest and accelerate to a speed of 1.7 m/s after 1 min. a)Find the work done by cable...
October 9, 2012

Repost-Physics 1
A car is pushed along a long road that is straight, horizontal, and parallel to the x direction. a)The horizontal force on the car varies with x as shown in the figure. What is the work done on the car by this force? (Let a = 100 N.) _____J b)What is the work done by gravity ...
October 9, 2012

Repost-Physics 1
A horizontal force of 30 N pulls a block of mass 2.5 kg across a level floor. The coefficient of kinetic friction between the block and the floor is ìK = 0.25. If the block begins with a speed of 2.0 m/s and is pulled for a distance of 18 m, what is the final speed of ...
October 9, 2012

Repost-Physics 1
A skier of mass 109 kg travels down a frictionless ski trail. a)If the top of the trail is a height 218 m above the bottom, what is the work done by gravity on the skier? _____J b)Find the velocity of the skier when he reaches the bottom of the ski trail. Assume he starts from...
October 9, 2012

Repost-Physics 1
Consider a roller coaster that moves along the track shown in the figure below. Assume all friction is negligible and ignore the kinetic energy of the roller coaster's wheels. Assume the roller coaster starts with a speed of 19 m/s at point A. Find the speed of the roller ...
October 9, 2012

physics
A 110 kg object moves in a horizontal straight line with an initial speed of 54 m/s. If it is stopped along that line with a deceleration of 1.90 m/s2 what magnitude of force is required?
October 9, 2012

physics
A 110 kg object moves in a horizontal straight line with an initial speed of 54 m/s. If it is stopped along that line with a deceleration of 1.90 m/s2 what magnitude of force is required?
October 9, 2012

Physics
assuming there is no air friction, A) yes B) (10+1.35)-8.65= 2.7m
October 9, 2012

Math
10/2 X - 3/2 X= 7/2 X= 3.5X
October 9, 2012

4th grade math
no problem
October 9, 2012

4th grade math
72
October 9, 2012

Physics 1
Consider a roller coaster that moves along the track shown in the figure below. Assume all friction is negligible and ignore the kinetic energy of the roller coaster's wheels. Assume the roller coaster starts with a speed of 19 m/s at point A. Find the speed of the roller ...
October 8, 2012

Physics 1
A skier of mass 109 kg travels down a frictionless ski trail. a)If the top of the trail is a height 218 m above the bottom, what is the work done by gravity on the skier? _____J b)Find the velocity of the skier when he reaches the bottom of the ski trail. Assume he starts from...
October 8, 2012

Physics 1
A horizontal force of 30 N pulls a block of mass 2.5 kg across a level floor. The coefficient of kinetic friction between the block and the floor is μK = 0.25. If the block begins with a speed of 2.0 m/s and is pulled for a distance of 18 m, what is the final speed of the...
October 8, 2012

Physics 1
A car is pushed along a long road that is straight, horizontal, and parallel to the x direction. a)The horizontal force on the car varies with x as shown in the figure. What is the work done on the car by this force? (Let a = 100 N.) _____J b)What is the work done by gravity ...
October 8, 2012

Physics 1
Two railroad cars, each of mass 2.2 104 kg, are connected by a cable to each other, and the car in front is connected by a cable to the engine as shown in the figure below. The cars start from rest and accelerate to a speed of 1.7 m/s after 1 min. a)Find the work done by cable...
October 8, 2012

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